It knows how warm it’s been.

The plants in your beds, insects that visits them, and fungal spores waiting for the right moment run on the same clock. Not the one on your wall, but accumulated heat. This is the garden’s native measure of time. And once you learn to read it, you start to better anticipate what will happen in the garden rather than just reacting to it.

After the pest alert last week, I had a couple people asking about Growing Degree Days and how they work.

Growing Degree Days (GDD) are a running total of heat above 50°F, the temperature below which most warm-season plants and insects essentially pause their development. Above 50°F, biology accelerates in direct proportion to warmth. The formula takes 30 seconds: average your daily high and low, subtract 50, add the result to your running total. A warm July day might contribute 30 GDD. A cool April day might contribute 5. The calendar calls both “one day.” Your garden knows the difference.

I’ve been tracking GDD in my production work and NYBG teaching for years, and it’s one of the most useful lenses I can hand a gardener. Right now in Westchester, we’re sitting around 900-1000 accumulated Growing Degree Days for the season. Squash vine borer adults, one of the most common reasons zucchini plants collapse in July, typically begin flying at 900 GDD. That indicates their first flight has just begun. Not a guess. A reading from the same clock your garden is already running on.

That’s what GDD does. It lets you track where you are in the season’s rhythm. Rather than a guess or average date, we can use the biological reality unfolding in your beds.

The Math Takes Less Than a Minute

You don’t need a spreadsheet (although I like those too!). You need the weather app already on your phone.

Each morning, look at yesterday’s high and low temperatures. Add them together, divide by two, subtract 50. If the result is negative, write zero. That’s your GDD for the day. Add it to a running total and you’re tracking your season.

June 11th in Hastings: high of 90, low of 71. (90 + 71) ÷ 2 = 80.5, minus 50 = 30.5 GDD. A week of weather like that adds roughly 200 GDD to your total. Three cool weeks in April with averages around 55°F might add only 30. The calendar said the same amount of time passed. Your garden would disagree.

If you’d rather skip the math, Cornell’s free NEWA degree day calculator (newa.cornell.edu or Climate Smart Farming}) pulls from actual weather stations across the area and keeps the running total for you. No account required.

What GDD Reveals That the Calendar Hides

That seed packet promising tomatoes in “75 days” is technically accurate. But 75 days of what?

A tomato transplanted in a warm May when soil is already at 65°F accumulates heat at a completely different rate than one put in the ground during a cold, wet spring when soil temperatures barely break 58°F. The calendar won’t tell you why one plant seems a month behind schedule. GDD will.

This is also why some seasons feel dramatically earlier or later than others. A warm April in Westchester can put your garden 2–3 weeks ahead of a cool one in biological terms. Climate Central analyzed 50 years of data and found that the Northeast has accumulated roughly 500 more GDD per season than it did in 1970. That’s a measurable shift. If the planting advice you learned 20 years ago sometimes seems slightly off, this is part of why.

In this season’s GDD graph we can see that although we are well historical averages. April and early May were relatively flat - with it being exceptionally cool. It was only really a few days right around April 1st and April 15th that we got a big spike. But if we didn’t have vegetables in the garden before April 15th or they were too young to make good use of it - our gardens felt a little slow to start. But now with the past week things should be starting to grow fast!

A Pest Calendar Built on Heat, Not Dates

A handful of the most common vegetable garden pests also have well-documented GDD thresholds, researched by Cornell, Penn State, and UMass extension services over decades. They’re the result of field research across thousands of observations.

A few thresholds worth keeping:

900 GDD: Squash vine borer adults begin flying. Cucumber beetles emerge from overwintering sites in woodland edges. In a typical Westchester season this lands between late June and mid-July. In 2023, a notably cool spring, many Hudson Valley gardeners didn’t see SVB pressure until late July. In a warm year, it arrives earlier. Same pest, different date, same GDD.

631 GDD: Peak European corn borer first-generation flight. Relevant for sweet corn growers. A second generation emerges around 1,400 GDD and also targets pepper fruit. This second batch definitely wacked back my peppers 2 years ago and I had the grubs in lots of my bell peppers.

354 GDD (base 39°F): Peak seedcorn maggot flight. This one explains a mystery many gardeners have encountered: beans or cucumbers planted in cold, wet May soil that simply never came up. The maggots destroyed the seeds before germination. Waiting until soil temperatures are consistently above 60°F solves the problem. GDD tracking tells you when you’re actually there.

Add It to Your Garden Journal

The best version of this tool is personal. Extension service thresholds are regional averages. Your specific beds, in your specific microclimate, will develop their own pattern over time.

If you like keeping a garden journal, try adding two columns: daily GDD and season total. Then note when you first see each pest, when your tomatoes set their first flower, when the first bean is ready to pick. After two or three seasons, you’ll have your own reference. You’ll know that in your garden, squash vine borer pressure shows up around 880 GDD, or that your beans germinate reliably once the total clears 400. That’s not a regional average. That’s your garden’s data.

Commercial crop scouts maintain logs like this as a core part of their job. There’s no reason an interested home gardener can’t build the same thing in a notebook.

As always, hit reply with questions. If you want to know where your season stands right now, Cornell’s NEWA tool will tell you in about 60 seconds: newa.cornell.edu/degree-day-calculator. Set the base to 50°F and I tend to use the weather station at the White Plains Airport.

All the best,
–Nick

I’ve started finding their eggs on client’s zucchini plants this week, which tells me we’ve crossed into the right conditions for adults to be active. Here’s why timing matters: the eggs are the easiest time to control them. Once they hatch, things get a lot harder.

How the timing works:

SVB adults emerge when accumulated heat (measured in growing degree days) hits around 800-900 degrees. With the hot weather this past week, we’re there! The adults are wasp-like, orange-bodied, and they fly fast and low during the day. They lay small, flat, reddish-brown eggs directly on squash stems, usually near the base of the plant.

Those eggs take about 7-10 days to hatch. Think of it as a timer. The moment a larva hatches, it bores straight into the stem and starts feeding from the inside. By the time you see the wilting, the borer is well-established and there’s no reliable way to reach it.

What to do right now:

Check your zucchini, summer squash, and other cucurbits. Run your fingers along the base of each stem and the undersides of leaf joints. You’re looking for small reddish-brown dots, about the size of a sesame seed, stuck to the surface.

If you find eggs, remove them. Use a fingernail or a piece of tape to pull them off cleanly. Check again every few days. The adult flight window lasts a few weeks, so this is a recurring job until after July 4th.

If the eggs hatch, the new larvae immediately start to burrow into the stem of our plants and eat the Xylem (the ‘veins’ of the plant that carry water from the roots up to the leaves) and the whole plant will start wilting and dying. We can cut open the stem later and try to dig out the larva but it’s time consuming and pretty gross. So this is a great time to get ‘em when they are at their most vulnerable.

If you want help keeping up with this kind of pest timing through the season, that’s exactly what my garden maintenance program covers. Just reply and I can tell you more.

P.S. for more information about these guys go check out: Arthropod Pests of NYC Vegetables, UMass Extension · eOrganic · UNH Extension

--Nick

Every spring I see the same pattern in gardens across Westchester: transplants go in the ground, look fine for a week, then stall. Growth slows, lower leaves yellow, and by July the plant is playing catch-up with the season instead of running ahead of it. This is transplant shock, and most gardeners underestimate how severe it actually is.

When a transplant leaves its pot, it can lose or damage more than half of its root system, especially the delicate root tips where their ability to absorb water and nutrients is greatest. All of a sudden, the plant is running on reserves while it tries to rebuild. In warm, biologically active soil, recovery takes 7-14 days. In a depleted soil with little microbial activity, it takes much longer, and that lost time shows up in your harvest.

Over 15 years of farming and gardening and in my NYBG teaching, I’ve refined a planting-day routine that addresses transplant shock at multiple levels. It takes about 20 extra minutes for a full bed. Here’s the formula, and more importantly, why each piece of it works.

The Formula

1. Soil test in March or April to identify pH or nutrient problems before planting

2. Work compost into the top 6 inches to inoculate the soil with a living microbial ecosystem

3. Broadcast alfalfa meal and feather meal to prime a slow-release nitrogen supply

4. Dip every transplant in diluted fish and seaweed emulsion just before it goes in the ground

Each step targets a different part of the problem. Let me break down what’s actually happening in the soil when you do this.

Start with a Soil Test (Before You Plant Anything)

The soil test comes first, and it should happen in March or April in Westchester, not at planting time. The reason is pH lock-out: at the wrong pH, nutrients that are physically present in your soil become chemically unavailable to plants.

Here’s the why. Phosphorus, which roots need for early cell division and growth, binds into unavailable compounds when our soil pH drops below 5.5 or rises above 7.5. Calcium, magnesium, and sulfur become less available in acidic soils. Iron, zinc, and manganese become insoluble in alkaline soils. You can fertilize heavily and still see deficiency problems if pH is working against you.

If your test shows you need lime to raise pH, those amendments need 4-6 weeks to work before they affect nutrient availability. That’s why March testing matters. By planting time in mid-May, the correction has had time to take effect.

Compost: Inoculating the Soil with Life

Before reaching for any bag amendment, work 2-3 inches of finished compost into the top 6 inches of your bed. This step is about introducing biology, not nutrients.

The slow-release amendments that follow (alfalfa meal and feather meal) only work if soil microbes are present to break them down. Compost delivers the bacteria, fungi, and other organisms that colonize around plant roots and begin decomposing of organic matter. Without this microbial foundation, your organic fertilizers sit largely inert. With it, they become part of a living system that releases nutrients continuously through the season.

Alfalfa Meal and Feather Meal: The Slow-Release Nitrogen System

These two amendments work together to cover nitrogen across two overlapping release windows.

Alfalfa meal (roughly 2.5-1-1 NPK) releases nitrogen over 4-8 weeks as soil microbes break down its amino acids. But nitrogen is only part of what alfalfa contributes. It contains a naturally occurring compound called triacontanol, a long-chain alcohol that enhances photosynthetic efficiency by upregulating RuBisCO, the primary enzyme plants use to fix CO2 into glucose. In practical terms, plants treated with alfalfa-amended soil can produce more biomass from the same amount of light.

Feather meal (12-0-0 NPK) is almost pure nitrogen, and it releases on a longer arc. The keratin protein in feathers resists microbial breakdown, so soil bacteria must produce specialized enzymes to slowly unlock the nitrogen. About 75% releases in the first three months, the remaining 25% over months three and four. That means our gardens are getting the most nitrogen when our plants are most hungry for it and later on in August and into September they need less as they transition to needing more potassium and phosphorus to drive fruit growth.

In the spring I walk along the beds and use a old pint size take-out container (mine used be a clam chowder from Bread and Brine - yum!) to scatter the alfalfa meal and feather meal across the top of the bed and then rake out a layer (.5-1” depending on the condition of the soil) of compost right on top. Finally I just try to take a minute to use a hoe or cultivator to work it into the top of the bed so that all that new soil life can go to work!

Together, the two amendments create a sustained release of nutrients from planting through late summer.

The Transplant Dip: Addressing Shock at the Root Level

Just before each transplant goes in the ground, dip the root ball in a solution of fish emulsion and seaweed extract diluted at roughly 2 tablespoons of each per gallon of water. This step works in the 24-72 hours after planting, when the plant is most vulnerable.

Fish emulsion provides immediately available amino acids that root systems can absorb directly, without waiting for microbes to break it down. These amino acids help damaged roots begin rebuilding faster. The phosphorus in fish emulsion also supports root cell division specifically.

The seaweed extract addresses the hormonal disruption that’s part of transplant shock. Kelp contains natural auxins and cytokinins, plant growth hormones that stimulate root cell division and elongation. These auxins and cytokinins help ensure that the plant’s root system bounces back strongly and quickly leading to happier healthier transplant!

I take an old bucket around with me to gardens and make up a 2 or 3 gallon batch of it at everyone’s house. Before I plant I just drop the whole transplant (gently!) right in the bucket and let it sit for a couple minutes so the emulsion seep right through the root ball and then plop him right in the ground. At the end of day I pour any extra fertilizer right over to the top of the new transplants and then water everyone in thoroughly. Nice and easy.

The dip doesn’t eliminate transplant shock, but it gives roots the materials and hormonal signals they need to begin recovery immediately.

Putting It All Together

None of this is complicated, and each piece adds maybe 5 minutes to planting day. The soil test and any pH correction happen weeks earlier. The compost, alfalfa, and feather meal go in when you prep the bed. The dip happens at the moment of transplanting.

What you’re building is a layered system: pH corrected so nutrients are available, biology established so amendments can break down, nitrogen released across a 4-month arc, and roots supported through the most vulnerable window. By mid-July, when untreated transplants in local gardens are yellowing and stalling, yours should be growing at top speed!

Questions about what your soil test results are telling you or which adjustments make sense for your beds? Just let me know or come say “Hi” at the Farmer’s Market!

All the best,
--Nick

As the gardening season winds down your shovel has been faithful all season long and now its time to show it some TLC too! Clean, sharp tools not only make gardening more enjoyable but also help reduce strain on your body and allow your tools to last for years to come. Here’s your quick guide to winter tool storage:

Basic Cleaning (Your First Line of Defense)

• Remove all soil and debris with a stiff brush - pay special attention to joints and crevices

• For stubborn sap or oils, use rubbing alcohol on a clean rag

• Ensure tools are completely dry before storage

Rust Treatment & Sharpening

1. For rust removal:

   • Soak rusty areas in white vinegar

   • Scrub with steel wool until clean

   • For heavy rust, start with 60-grit sandpaper before moving to steel wool

   • Wipe completely dry after cleaning

2. Sharpening guide:

   • Choose a single-cut file for shovels, hoes, and larger tools

   • Position the file at a 35° angle to the blade (start by laying it at 90° (perpendicular to the blade), tilt it halfway to 45°, then a smidgeon more)

   • Use smooth, even strokes from one side to the other

   • 5-10 strokes usually suffices

   • Finish by applying a light coat of mineral oil to all metal surfaces

Handle Care & Protection

• For varnished handles:

  • If coating is intact, simply clean and store

  • Otherwise it might be worthwhile to sand off the worn varnish and treat as below.

• For unvarnished or worn handles:

  • Sand smooth, working up to 120-grit

  • Apply boiled linseed oil generously

  • Let soak 20 minutes, then wipe thoroughly

  • CRITICAL SAFETY: Dispose of oily rags by laying flat outdoors or in a bucket of water - they can spontaneously combust if wadded up!

Essential Materials Checklist

• Stiff bristled brush

• Steel wool

• 60-grit and 120-grit sandpaper

• Mineral oil (baby oil works great)

• Boiled linseed oil or tung oil

• Single-cut file

• Clean rags

• Rubbing alcohol

• White vinegar

Pro Tip: You’ll be amazed at how much easier gardening becomes with properly sharpened tools. Your back will thank you come spring!

By late March, the gardening itch is unbearable. The soil’s thawing, last week’s 60 degree days already got you antsy, and you’re ready to dig. Problem is, tomatoes won’t go in for five weeks. Peppers should get another week after that. But onions and leeks? They’re ready now. In fact, late March through April is exactly when they should be planted.

This is the overlooked angle on alliums. Not the complicated variety selection or the microscopic pest management. Just the simple fact that onions and leeks are the first to the party when the spring weather finally arrives - weeks before you can plant anything warm-season.

I’ve been growing these for years here in Westchester. Let me walk through what actually works for transplants planted in late March and April.

The Allium Family: What They Have in Common

Onions, leeks, and garlic are all alliums. They’re cool-season crops originally from Central Asia and the Mediterranean. What matters for us: they all prefer the same soil conditions and have nearly identical fertilizer and water needs.

Soil: They want fertile, well-drained soil with pH between 6.2 and 6.8. Heavy feeders, so work in 1 to 2 inches of compost before planting. If your soil tends to stay wet or clay-heavy, they are a good candidate for your raised beds to improve drainage.

Light: Full sun. Six hours minimum, but they perform better with 8 or more.

Water: About 1 inch per week, consistent. They prefer moist soil but not waterlogged.

Fertilizer: High nitrogen early (while they’re making tops), then dial it back. Onions specifically need you to stop feeding once they start creating bulbs.

If you can give alliums these conditions, you’ll have success. The differences come in timing and the specific care each crop needs.

Planting Onions: Late March Through April

If you have transplants, they should be pencil-thick (about 1/8 to 1/4 inch diameter) and around 8 inches tall. If they’re taller and unruly in the tray, trim the tops back to 5 inches before planting. It sounds rough, but it redirects energy to the roots.

Spacing and layout: Plant them 4 inches apart in rows 12 to 18 inches wide. Three rows fit nicely in a standard 36-inch-wide bed. An 8-foot bed gives you 72 plants. Expect 25 to 40 pounds of storage onions if conditions cooperate.

Planting day: Make a shallow furrow with your finger or a small tool. Nestle the transplant in so the base sits just below soil surface and the green top comes up cleanly. Firm soil around it gently. Water immediately. They tolerate frost, so an unexpected cold snap won’t hurt them.

First month: Water when the top inch of soil dries out - this is a lot easier as we are planting them in spring when the soil is naturally more moist. Feed with a balanced fertilizer every 3 to 4 weeks. They’re building green tops right now, and you want them vigorous.

June management: By mid-June, watch for the tops to start looking lush and thick. You’ll also notice something happening underground. In July, the tops will start looking a bit less perky. That’s normal. The plant is shifting energy downward, bulging out the base. When you actually see soil cracks around the bulbs and the shoulders push up through the soil surface, that’s your signal: stop all fertilizing. This is critical. Nitrogen after the bulb starts forming just delays the whole process and gives you soft, thick-necked onions that won’t store.

Late summer: By August, the tops start falling over and turning brown. This is the onion telling you maturity is near. When 50 percent of the tops are flat on the ground, pull them. Don’t leave them in the soil once necks start softening.

Planting Leeks: Same Time, Different Care

Leek transplants look similar to onion transplants: pencil-thick, 8 inches tall, with that bundle of green leaves. But planting them is different.

The dibble hole: Use a dibble stick, a piece of rebar, or even a sturdy broom handle to make a hole straight down 5 to 6 inches deep. Drop the seedling in so only 2 to 3 inches of green leaves stick above the soil surface. Here’s the part that surprises people: do not firm the soil around the transplant. Leave it loose. Let rain and irrigation gradually fill the hole in over a few weeks. This creates exactly the blanching effect you want without making you do extra work later.

Spacing: 6 inches apart in rows 12 to 18 inches wide. Same as onions, basically.

Early growth: Keep them watered consistently. Mulch around them once they’re established. They’re heavy feeders, so side-dress with balanced fertilizer in late May and again in mid-June.

Summer hilling: Starting in late June or early July, when the leeks are 12 to 15 inches tall, hill soil around the stems. Just mound loose soil up around the base, burying another 2 to 3 inches of the white stem that’s below the leaves. Do this once more in August if you have time. Each hilling buries more stem and excludes light, creating the long white shaft that’s the whole point of growing leeks. By fall you’ll have 6 to 8 inches of white stem per plant.

Timing varieties: King Richard matures in about 75 days, so it’s ready by late June or July. Tadorna takes 110 days or more and doesn’t mature until October or November. If you plant both at the same time in April, King Richard gives you an early harvest and Tadorna carries you through fall and winter. Two different crops from one planting date.

What Happens Next

By mid-May, both your onions and leeks should be established and growing steadily. At this point, they’re low-maintenance. Water during dry spells, fertilize every few weeks through June, and then let them do their thing.

In mid-to-late July, start watching your onion shoulders. When they lift, fertilizing stops. Leeks keep eating through July and August but start slowing their nitrogen needs by late summer. If you see thin white lines on the leaves in late April or May, that’s allium leafminer moving in. Row cover put on before mid-April stops it completely. Once you’re into June, the flight is usually done.

The real payoff comes in stages. Onions are done by September, cured and stored. King Richard leeks come in July. Tadorna and American Flag carry you through November, December, and into January if the ground doesn’t freeze solid. That’s four months of harvest from alliums alone.

The work is minimal. The results are real. And you get to actually garden in March when the fever first hits!

Questions about timing, spacing, or what to plant? Reply anytime and find them on the Website:

Leeks

Onions

All the best,
Nick

There are three good windows to apply compost each year and each one works a little differently. But if you only do one, do this one.

Spring prep (March-April): Work it in

Spread .5-2 inches of compost across your beds and work it into the top 6-8 inches of soil. The goal is to inoculate the whole soil profile with the active biology, not just the surface. Think of it like stirring a starter culture into the whole batch, not just spooning it on top.

This is especially valuable if your beds have gotten tight and compacted, or if you’re starting a new garden. Watch out for soil in poor tilth. If your soil is feeling powdery and can’t form clumps (aggregates) that hold together until pinched or if it all locked together in large pieces that are hard to break apart, then you need a little extra help. I would recommend adding a 2 inch layer of compost to your garden to remediate and reintroduce that biology.

If your soil is already in great shape and has worms, invertebrates, fungi, etc, only add 1/2 an inch layer (sprinkle until you just can’t see the soil underneath).

This also the perfect moment to mix in slow-release nutrients — alfalfa or feather meal for nitrogen, bone meal for phosphorus so everything is in place before planting season kicks off - a soil test can be the perfect thing to make sure we are adding the right nutrients in the right amounts!

Get Help with a Soil Test

Mid-season (June-July): Top-dress around plants

Once plants are established you can’t easily work compost into the soil without disturbing roots. Instead, spread a thin layer — about 1/2 inch — over the root zone and cover it with mulch. The worms will do the mixing for you. This is a good mid-season boost for heavy feeders like tomatoes, squash, and peppers.

Fall (October-November): Layer and leave it

After the plants come out, spread 1/2 to 2 inches across the empty beds and cover with mulch. The FBI spend all winter slowly breaking it down, and by the time you’re ready to plant in spring those nutrients are already integrated and ready to go. This is also the right time to add any mineral amendments from a soil test like Azomite or lime and they’ll have all winter to settle in.

Do this consistently and your garden gets measurably easier and more productive every year. Soil that started as compacted clay starts holding water better, nutrients stop leaching out after every rain, and plants just thrive!

If you want the Vermont Compost I use in my own garden, you can grab it here: Compost Plus

All the best,
--Nick

Your garden soil isn’t dirt. It’s a jungle.

Underneath every healthy vegetable plant is a whole ecosystem of old roots, decaying leaves, blooming fungi, and hungry bacteria. This microscopic world is what actually feeds your plants—breaking down organic matter, opening up pore space for air and water, and making nutrients available to roots. Compost is how you supercharge it.

Compost is just decomposed organic matter—your banana peels, grass clippings, and fallen leaves broken down by what I call the Soil FBI: Fungi, Bacteria, and Invertebrates. A good compost pile creates the perfect environment for them to multiply: warm, moist, filled with diverse food sources. When we talk about “finished” compost, we mean the point where those populations have peaked and most of the original material has broken down. That’s when it’s most valuable—loaded with active organisms ready to spread into your garden.

When you add finished compost to your beds, the FBI that grew in the pile spread across your garden beds, increasing the diversity and amount of microbial life. They break down old organic matter and make nutrients available again. They open up pore space in tight, compacted soil (especially important for Westchester’s heavy clay). They create humates—compounds that hold onto just the right amount of water and nutrients, keeping them available to plants long after the last rainfall. The effects build over time, especially when you apply compost regularly.

But quality matters, and I learned this the hard way.

A few years back I ordered 20 cubic yards of compost from a supplier I hadn’t used before. They delivered it in October, and when I walked out to inspect the pile, the smell hit me first—sharp and sour, like Windex. The compost was black goop, wet and slimy. It had gone anaerobic somewhere along the way, probably sealed up too tight or too wet for too long. The wrong organisms took over and the whole biology shifted toward ammonia-producing bacteria. Not what you want in a vegetable garden.

Luckily it was fall. I had access to mountains of leaves from neighborhood cleanups, so I mixed in as much carbon as I could—huge piles of dry leaves worked into that black mess. Then I let it sit all winter. The biology rebalanced itself, the pile heated up and cooled down, and by spring it had actually finished composting properly. It turned into decent compost, but it took six months of babysitting and a lot of free leaves to fix the problem.

I don’t have time for that anymore. Now I’m pickier about sources. Good compost smells earthy and cool with a crumbly texture. It shouldn’t be dried out completely (the organisms need water) or sealed in plastic bags where they run out of oxygen. And it should come from suppliers who understand what they’re making—not just piling stuff up and hoping for the best.

This is why I’m now pickier about where my compost comes from. Vermont Compost is what I use in my potting mix and recommend to clients. They understand the ecology of their product, they don’t cut corners, and it shows up consistently high quality with active, diverse biology.

If you want some of the same compost I use, you can find it here: Compost Plus

Leter this week I’ll cover practical application—when to apply it, how much to use, and the best methods for different situations.

All the best,
--Nick

P.S. I would love to build out these “Deep Dive” emails. Please feel free to share with friends and encourage them to sign up for indepth looks at gardening topics all season long. Thanks so much!

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What is Grafting?

At its core, Grafting is transplant surgery for plants! We join plant parts from 2 (or more) different plants so that they will heal into a single plant. In tomatoes, peppers, eggplants, etc. we are usually connecting the top (scion) of one variety to the roots (rootstock) of another variety. Gardeners and nurserymen have been conducting this surgery for centuries in greenhouses just like the ones we are in at Lyndhurst. Even this time of year, as you walk down your street, you will see evidence of this surgery all over our cultivated landscape. Look closely at the ornamental cherry trees and you can quickly find a graft union (a ring of healed wood about 4 inches above the soil surface) where a decorative variety was grafted to join it to a set of hardy roots. The nursery was able to capture the disease fighting and height restricting powers of the root system to the beautiful, flowering powers of the branches.

Tomato grafting is very similar. I plant 2 tomatoes for each final plant we are going to get. The rootstock varieties (I’m using Maxibel and Estimino) and the Scion varieties (Black Krims, Striped German, Rose de Burne and even Martha Washings) all get seeded around the same time. When their stems are the same size I will remove the tops off of both varieties and use a little clip (like a small section of rubber straw) to hold the scion on top of its new rootstock (the one that will grow the strong root system). Careful to line up the two vascular systems, I will place the new plants in a very warm, moist and dark environment to encourage the plant heal quickly and strongly. Before long it will be back on the greenhouse bench and then ready to go out into the garden!

Why Grafting?

It seems like a lot of work but by grafting tomatoes we can help them fight diseases, increase their strength and harvests, as well as extend their lifespan deep into the fall. Rootstocks are genetically better at fighting off soil diseases like fusarium wilt which I see throughout Hastings, Irvington, and Scarsdale. In late July look for leaf branches that are half yellow and half green - the tell tale sign of fusarium wilt. This happens as the fungus clogs Xylem (the water carrying arteries of the plant). Estimino rootstock naturally fights off the fusarium wilt hyphae as they try to enter to the roots and stops them from spreading through the vascular system. This way we can prevent the disease without feeling pressure to resort to any pesticides or chemical solutions, especially in a garden where we don’t usually have the space to just plant our tomatoes in a different place for 5 to 7 years while we wait for the fungus to naturally go away.

In addition, these rootstock build larger root systems faster that gather more water and nutrients and drive larger and healthier fruit. These rootstocks are bred for speed! This is the equivalent of dropping some super sports car engine in our around-town car. As the root systems grow faster and larger than normal ones, they collect more water and nutrients from the soil - helping us here in Westchester to weather some of those hot, dry Augusts and forage the nutrition our plants need to grow large fruit into November as long as we don’t get an early cold snap.

All that extra ‘umph’ from those stronger roots all result in more delicious tomatoes. We can focus all these benefits and channel them into some of our best tasting, traditional heirlooms that have been bred for flavor year over year in order to get the best of both worlds. Comparison tests have see anywhere from 30% to 120%+ yields over the course of the season. Oregon State University trials show a 97% increase in Early Girl fruiting when grafted onto Maxibel. That makes a huge difference in a small garden where we want every plant to do the best it possibly can.

Why this matters here!

This is a huge deal for gardeners here in Westchester. A lot of us our constrained by access to space where we can get a lot of light. And some of us (who will remain nameless around here) still want to leave a little ground available for flowering and ornamental plants too! If we can get ever tomato to produce like 2 or more plants it means that we can expect more and more from out small spaces! On top of this, study after study demonstrates how grafted tomatoes are more efficient at converting water and nutrients into veggies on out table, making them an important choice as climate changes encourages us to better utilize our resources. Not to mention their robust roots systems allowing them to weather periods of drought or flooding better.

The Experiment:

In late February, I’m finalizing varieties for my personal tests (and my own garden). I’m focusing on varieties that will give me the best bang for the buck! Top contenders are indeterminate flavorful heirlooms that just don’t have the vigor or harvests of some of the newer hybrids. For instance, I’ll skip GinFizz, which although it has awesome flavor its also a relatively modern hybrid that yielded like gangbusters last season! Instead, I’m reaching for those classic heirlooms which just don’t have the disease or high yields as some of the more modern varieties - like Black Krim, Striped German, Rose de Burne and San Marzano.

I’ll be sure to keep you up to date here as the season progresses, so be sure to subscribe to the email list to see how it goes.

• In late February or early March we’ll do a behind the scenes look in the greenhouse at the grafting process - the surgery itself (!!), healing chambers, and early growth.

• In May how I am prepping the beds specifically for them and looking at priming the care and fertilization to make sure we get the most out of them.

• In late June well take a look at the first results - how they are performing as they start setting flowers and fruit.

• In August for a mid-season check-in and comparison of yields and disease pressure.

• Finally in Late October for the final results and full breakdown if they will have been worth the extra work and cost here in Westchester!

With luck there will be some limited amounts of extras available this season. If it’s something that you are interested in helping me experiment with then let me know and we will see if we set up a list for the overflow!

Questions about grafting for your garden? Hit reply or comment below. I’d love to help you think through whether this technique makes sense for your specific conditions and goals.

All the best,

--Nick

I start all my garden plans with a list of my own favorite recipes. Grow what you cook, eat more of what you grow and therefore have more fun doing the growing! If your family is a:

• Big Salad Family - Make sure you have plenty of ​lettuce​, ​cucumbers​, and​ cherry tomatoes​ (maybe some radishes too) in that garden!

• Pizza and Pasta Family -focus on ​basil ​and big ​paste tomatoes​ so you can make your own sauce this season – it’s better than anything store bought, I promise!

• Taco Family - tomatoes, cilantro, hot and sweet peppers, tomatillos, onions, radishes for garnish.

I break down our 3 or 4 most regular dinner recipes into their main ingredients and make sure that our garden focuses on those ingredients. Once those bases are covered and we have plenty of the tomatoes, zucchini, onions and crunchy head lettuce that our recipes demand, then I start filling out the rest of the garden with all my favorite extras. Our community garden is filled with ​green beans​, ​pickling cucumbers​, and sugar snap peas - all perfect for encouraging my kids to forage and snack on fresh food right in the garden.

I learned this lesson the hard way. My first few years gardening, I’d get excited with the seed catalog or at the farmers market and end up with all sorts of “new to me” veggies.. By August, I had eggplants I didn’t know how to cook and not enough of the basil I actually used every week. Now? Our garden produces exactly what we need most.

Now Browse With Purpose

Head over to the catalog and start wishlisting the varieties that match your plan. Our new wishlist feature lets you save everything as you browse, so when preorders open January 1st, you’re ready to go.

Not sure which tomato varieties are best for sauce? Which lettuce handles summer heat? Hit reply - I love talking through these decisions. And we can schedule a winter planning session to get your garden just right for you this spring.

All the best and stay warm out there!

–Nick