Growing Tomatoes, Part II: Sprouts!

By this point we shall assume that you, the intrepid future tomato gardener, have acquired the seeds of the variety (or varieties) that appeal most to you. If you’re a tomato fan it’s likely that you enjoy more than one example of the “love apple,” as it was known centuries ago. You might also be keen to try a new one along with your old favorite — but even if you’re just beginning with one cultivar, you’ll need to germinate your seeds to get started.

Vegetable seeds require heat, light, air and moisture to sprout. At first they don’t actually need any soil; the seed itself contains enough ‘food’ to get itself started with a set of immature leaves and rootlets. Even if seeds are set in a rich medium, all the soil will do is hold up the sprout as it unfolds, not feed it. Believe it or not, it’s actually a bad idea to germinate your seeds in a rich planting medium. The reasons are mold and mildew.

Both these microscopic fungi may be present in a rich loam, and they are only waiting for some moisture to come to life, themselves. The danger they pose to your germinating seeds is extreme, because the fungi – still invisible to the naked eye— will grow faster than your seedlings and will feed upon them. This is known as “damping off.” The first thing you notice is that your young sprouts, emerging and vigorous the day before, appear to be drooping from lack of moisture. Typically more water is given. This serves to feed the fungi more than your seedlings, and within another day or two the sprouts will likely be terminally weakened or even already dead. Often the spot under attack is the plant’s stem, right at ground level, and the plant topples over like a mature tree felled by an invisible woodsman.

[NOTE: Always wash your hands thoroughly before you handle your tomato seeds, and this is especially important if you are a smoker. Tobacco commonly carries a pathogen within it known as the “Tobacco Mosaic Virus.” This virus doesn’t seem to affect smokers’ health any more dreadfully than the tobacco it accompanies, but it spreads by contact. If you smoke, it’s likely to be on your fingers. If you then handle seedlings or plants it will transfer to your tomatoes, capsicums, and any other members of the Nightshade Family, in the greenhouse or in your garden. It will infect lots of other plants as well. The result is sometimes known as “Chex” because it causes a dark ‘netting’ to appear on the skin of the fruit, as if it was checkered. It doesn’t appear to harm the tomato except to make it unsightly, but I have heard that it also impacts the keeping quality.]

I purchase a proprietary seed-sprouting medium from the local nursery, but you can use your own medium as long as it’s light and friable, sterile, and almost nutrient-free. Use a small wooden flat, a tray or even just a dish with a lip, and put a layer about half an inch thick of the sprouting mix into it. Dampen it without making it sodden. Then plunk down your tomato seeds on the surface one at a time; it’s better to use something like an ordinary toilet paper tube to do this, rather than your fingers, if you cut the paper tube lengthwise to make a semicircular trough. Put the seeds in this and tap the side with your finger. It will ooch the seeds along in more or less single file and drop them off one at a time, if the tube is held at a gentle angle.

Sprinkle only a little bit more of the sprouting mix over the seeds, tamp down gently, and set the dish in a warm spot. A tomato seed’s germination is triggered by heat and moisture more than by sunlight, but if you have a warm and sunny southerly-facing window ledge, you can make use of that. I put my sprouting tray on the floor beside my wood stove, and this works very well. Check it every day, once or twice, to make sure it’s neither drying out nor sopping.

In a few days, seeds will germinate or “pop,” and a tiny green set of immature leaves will appear on a little stem. Very soon, these successful sprouts will need to be transferred to their first bed of soil, in a four inch squarish plastic pot.

To fill those four inch pots I once again find it safer to purchase a commercial brand, looking for an organic Potting Soil Mix with some nutrient in it, but not a great deal. I follow the guidelines of a brilliant English master gardener named Alan Chadwick, which he called the “Breakfast / Lunch / Dinner” system. “Breakfast” is what’s in the four inch pots, a modest amount of nutrient; this graduates to “Lunch,” a somewhat richer potting mix in the next stage (1 gallon pots); and finally “Dinner,” the richest medium of all, your garden bed.

Lightly fill a four inch pot with some dampened potting mix almost to the top, then with your pinky finger poke two holes about an inch deep down into the mix, as far apart as they can be without touching the sides, in each pot. You could use a clean popsicle stick (they’re also called “craft sticks”) for this. I employ one, or a similar scooper made of stainless steel, to gently shovel up the tomato sprouts one at a time, keeping a nice jacket of damp sprouting mix around the rootlets, and plop them gently into the holes you just poked. The leaves and just a little bit of stem should stick up over the level. When each hole is filled, pick up the pot and thump it lightly on the tabletop, which should gently collapse the holes evenly around the two sprouts’ stems, aiming them straight up. Water VERY gently (misting is best) to settle the potting mix, adding a bit more if necessary to fill in any voids.

If you are obliged to touch a seedling with your fingers during this process (say, to pick up a fallen one) first make sure your hands are clean, and second only handle the seedling by the leaves – never by the stem!

Put all your filled four inch pots onto a tray (or just a plank of wood) and set it in a sunny but not necessarily too-warm spot. Tomato seedlings, once they make it alive through a potentially traumatic transplant, don’t mind coolness as long as they get plenty of LIGHT. The plant’s little green leaves are what’s feeding it now, and secondarily the nutrient in your potting mix. If you keep your sprouts in a warm area, they’ll quickly grow too tall and skinny and become very troublesome to handle without damaging them.

NEXT MONTH: Potting up, and prepping the planting bed…