So you want to have your best garden ever? I join you on this venture, and each year we strive to do better. A seasoned gardener knows all too intimately that some years are better than others due to factors well beyond our control, but a lot of little things at the beginning of it all directly effect how strong your starts become. So I’m digging and sharing my top tips we religiously implement that produce our hardiest, healthiest transplants.

Seedlings are undeniably the most endearing indoors friends of late winter, and brassicas comprise a large proportion of the party.

We love gardening from seed, from the endless options to bearing witness to the life cycle from seed to plate. It’s always been a huge focus of our garden journey, and thus garden planning. While it is nearly exclusively how we grow our food at this point, there were a few lean years where our garden was modest and our time short and our lives, well, enormously complicated, and we bought starts for many plants.

And guess what? The food tasted just as delicious and the joy just as deep, although the harvests weren’t as early as other years. However your path to growing food wanders, I am simply thrilled to know you are taking the steps to grow your own. It’s definitely the highlight of our years, and I hope it brings you the same joy and nutrition it does for us.

Before you jump into seed starting, you want to set yourself up for the best possible outcome: successful, thriving and strong plant starts. Because going through all the extraordinary — and often expensive — effort to source seed and supplies will only be as successful as your system and approach. We have a very specific way we grow our starts, and they are consistently vigorous and healthy. Over 20 years of growing from seed does that — it helps you hone and refine your craft, giving you this bounty of intrinsic knowledge from which you naturally draw your plant tending instincts.

In my heart of hearts I know it is more than just instincts. I know it’s experience, and for us that amounts to a collective four decades of growing and learning, and it’s the (now) innate process we implement to our land and our seed starting process that result in robust, healthy, and very productive plants. So I’m going to try to lay it all out for you, to spill my secrets, even the ones that are yet unknown to me. I will invite the keyboard to wander until I’m satisfied it has uncovered every last delicate morsel and peered inside each emergent blossom of this great mystery even I behold as a wonder.

The Glory of A Seed

In April the flower frenzy begins as I sow hundreds of flats of flowers into these 128 plug trays. I use these for zinnia, marigold, sweet alyssum, and cosmos.

Seed starting satisfies a lot of yearnings for me personally. First and foremost, to watch life literally erupt from a single seed, this ancient ritual, a world within a world waiting for the ideal conditions to flourish, is the most personally fulfilling, humbling, and exciting thing about gardening. To nurture that seed through to maturity where it then produces an entire head of cabbage, floret of broccoli, pounds upon pounds of cucumbers, basketfuls of tomatoes, overflowing bounties of beans and cucamelons and all the rest is the deepest, most satisfying work there is. It feels more like a privilege than anything else to grow alongside my plants each year, learning as much from my time in the garden as any other form of instruction.

Tucked just off our main living area these beautiful plant stands my husband built house our seedlings starting in early February annually. The sunny spot is supplemented with our four-bulb shop lights.

Growing from seed is so much a part of our lives that it takes over a physically large part of our living space from January through April - and we love that. Between snowstorms and arctic blasts of air, we huddle inside by the fire, watering our seedlings, bumping them up as needed, making room for new seeds and more and more flats of seedlings. We tend to these starts daily, checking for health and keeping a watchful eye on new germination. Providing the ideal growing conditions — basically creating a microclimate inside your home — is paramount to strong, healthy starts. This careful eye and thoughtful approach is what makes the difference between healthy and weak starts. As do a few other key ingredients.

The Right Stuff

For us, seed starting begins with the best growing medium, good quality and ample light, and warm soil. These are the three essential ingredients to successful and healthy garden starts sown indoors. And for us, it is the combination of these three elements that produce our strongest, healthiest veggie and flower starts.

The Growing Medium

Our soil block mixture blends compost and a lightweight soilless mixture with a small percentage of garden soil. While it contains available nutrients from the compost, we irrigate with a low concentration of liquid fertilizer after the first set of true leaves appear.

I always sow my tomatoes and peppers together, and they always end up growing at different rates. One of these years I may sow a tray of each, but we are limited by the number of lights we have so I cram as many soil blocks into each tray as I feasibly can, which is maxed out at 50.

Additionally, we maintain this light feeding schedule until they are transplanted into the garden, where we add our slow release complete organic fertilizer into their own transplant hole. On occasion, I will start seeds in potting soil and I typically amend it with about 1/4 to 1/3 compost before sowing. We like to ensure available nutrients are at the ready for our young plants and I hope after reading this you will, too.

Ready, Set, Lights

Lighting is another indispensable aspect to our seed starting setup and I’m convinced after over two years of sharing our journey with like-minded gardeners via social media that it is a large reason our starts look so strong and healthy. I shared a brief post in 2018 about our lighting setup. And after trying full spectrum LED lights that same winter, we remain staunch fans of our current system. This is something I get asked about frequently as people share their seed starting woes with me, and it bears repeating here.

You can see how we adjust the lights to meet seedling height requirements. Also visible are the heat mats that are still on the tomato and pepper tray (middle left shelf).

We use T8 fluorescent lights and leave them on all the time once the first seedlings emerge. Yes, that’s right. We bathe our starts in light, 24 hours a day, and you should try it, too. In a tray with multiple species and varying germination rates, this means some seeds may be exposed to light before germination, which we have never found to be a hindrance to our seed starting endeavor. Even things that require darkness seem to do okay, like calendula, because I am careful to bury and cover those seeds requiring darkness into the soil.

The other important aspect to our light setup is this: we use a 48” four-light ballast (see it here at my Amazon storefront) with half cool white and half warm white bulbs. This is a really important part of your light setup and as far as I’m concerned a non-negotiable for strong plants — you must use a mix of cool white and warm white bulbs as this gives a broader spectrum of light than either can provide on its own, thus more effectively mimicking natural sunlight. You really need to bathe these plants in your mock “sunlight”. Just think about how much stronger the real deal sunshine is than a few fluorescent bulbs. In the case of fluorescent, more is better, though not all light is equal. I cannot speak to other types of lighting except fluorescents.

A four-bulb ballast is what we consider a minimum amount of light for two 1020 trays, the standard size growing trays. If you use fewer lights or not the right spectrum balance, your plants may become leggy due to insufficient light (the botanical terminology for this is etiolation). Fluorescent light loses its power rapidly the farther you get from it, thus keeping them as close to the light as possible will alleviate their desire to stretch toward the dim light; it may not seem dim to you, but if they are leggy, it’s too dim for them.

Keep those lights close to those plants to minimize etiolation and give them as near outdoor light conditions as you possibly can in this indoor setup.

If you can, you should be bathing your starts in at least 2,000 lumens per square foot, with plants as close to the light source as possible, as mentioned above. With our setup, we produce almost 3,000 lumens per square foot. I recommend if you experience a lot of legginess with your starts, you need to check your current bulbs and see how they compare to our ideal output. If yours is less, see if you can find a way to bump up the output. You can look up the lumens of your bulb by doing a simple google search.

We keep our starts as close to the lights as physically possible without touching the light. It is okay if a plant touches the light, but ideally your starts are growing at similar rate (haha, let’s be real, that never happens for me!) and so you adjust the light for the entire tray, lifting it as needed so the starts are right below the ballast, receiving the maximum amount of light available. In reality, our lights end up at angles rather quickly; I try to seed trays thinking about germination rates and how my starts can thrive harmoniously under these lights until they are ready to be hardened off and then placed in the ground.

Let’s Get Cozy

Heating mats is the final and equally important key to healthy starts that we have been experimenting with over the past few years. In previous years, we used a heat mat until full germination of any given tray and then would back the warmth off the seedlings and allow them to acclimatize to our living space, which we keep at a cozy 67F.

Sown February 5 and germinated by February 12, these are our 2019 tomato seedlings. They are growing so strong and fast we will be potting them up and burying them deeply into a larger pot within the week.

Since 2018, we have been trialing keeping the heat mat on for our hot crops (tomatoes and peppers) for an extended period of time post-germination. We now maintain that extra soil warms at least three weeks post-germination for tomatoes, peppers, and other solanaceous crops like eggplants. Our experience has found that the plants thrive under these ideal soil temperatures. We then pot them up into 4.25” newspaper pots in another week or so and where they get buried deeply upon transplant. Should we run out of room in our main floor growing space, we have a spill over LED light in our cooler basement, where we use a very large heating mat that we keep on all the time because the air temperature lingers between mid-50s to low 60s).

Air Flow

I mention this because it is something a lot of well-well-respected gardeners use with their seedlings. At Seed to Fork, we don’t use fans, but I can definitely speak to their usefulness and you can decide for yourself whether or not you need this accessory. Many other garden gurus run oscillating fans near there starts to increase stem turgidity. This helps the plants develop strong stems and prepares them a little more for the real world, which, of course, is the end goal. Gently rubbing your hands over your starts every now and then does the same thing, and that’s how we meet this need.

Timing is Everything

Or is it? You know we like to push the season, and we start things on the very early side here. The upside of that is starts ready as early as the soil is. The downside is that some years the plants will be ready BEFORE the soil is. So it’s a bit of roulette, and if you want to play it safe, delay your planting just a little. And by delay I simply mean start them no later than mid-March (in zone 4) for tomatoes and peppers, your earliest brassicas would soon follow in the end of March for a late April transplant into a prepared bed.

The 2019 growing season was extremely stressful in April because our indoor starts grew so incredibly well. They were on a mission. It was a bizarre phenomenon, made more fantastical witnessing it happening to many gardeners the continent over. It worked out for us in the end, but not before potting our tomato starts up not once, but twice, eventually into 1 gallon pots. And many of them needed to be buried deeply at transplant.

Early Spring transplants often exhibit exuberant growth under our care, and we are always grateful when the soils are ready for our little garden to welcome them.

To ameliorate this unprecedented situation, I am delaying my tomato starts two full weeks this Winter. All my indeterminate tomatoes will get sowed in mid-February. Now, if my hunch is right, something will go awry and the starts will not demonstrate the same vigor and will to live they did last year and I’ll be fretting their underdevelopment.

I encourage you to play with your timing a bit, perhaps sow some at different intervals this winter. We will be doing this for our tomatoes, sowing our indeterminate tomatoes about a month earlier than our determinate tomatoes. I am taking this step in the hopes of delaying our harvest of determinate tomatoes until very late Summer.

Do What You Can

In the end, be realistic with your seed starting endeavors. Our first indoor seedlings were grown using only one two-light fluorescent fixture, and they were, I’m certain, predominantly tomato and broccoli starts (this was a long time before our cabbage craze arrived). We may have paired two lights together, which we propped up on cinder blocks on our kitchen floor. It was a humble and suitable beginning, sufficiently meeting our needs for our garden that we mostly sowed directly in the ground. As you know, gardeners evolve with each passing year.

Our seed starting setup mimics as closely as possible a sunny late Spring day: warm, inviting soils to encourage germination and growth, sunshine — and lots of it, and healthy, nutrient rich soil that has ample available water. These are the essential ingredients for seedling success, and I hope you’ve found something useful here to help propel your seed starting to the next level.

Growing Strong, Healthy Vegetable Starts from Seed