Don’t start more than you can manage. The more you have, the more you will have to juggle, the more likely a ball will drop. I’m a zone 6-ish suburban gardener with about 50 square feet for tomatoes and other annual edibles. I’ve learned that overcrowding gets me more diseases than fruit, so I really should grow only about a dozen tomato plants.
But how to decide between so many old favorites and even more new and dazzling catalog photos and descriptions? The struggle is real, especially if your seed stash grows by a few varieties each year. The good news is that seed last much longer than the date on the packet suggests. I’ve had great germination from 8 year old seed.
I really only want one plant of each variety, but I need to plant at least 3 seed each, one that may not germinate and one spare for the survival contest against pest, disease and myself. This math is specific for tomatoes, because of the high germination rate and relatively high seedling survival rate.
Tomatoes really want sun and wind, they are not indoor plants. In the average home, even with lights and all the frills, tomato seedlings won’t stay healthy for long. I prefer not to start them too early, so that they don’t have time to grow pale and skinny, break or die of disease.
Most seed packets will tell you to start 6-8 weeks before the last frost for your area, and to expect germination between 7-21 days. Folklore tells us to plant tomatoes after Mothers’ Day. I had someone tell me that his family believed in waiting until Fathers’ Day. So much depends on your specific growing conditions in your garden. I did a little experiment and learned that plants know when it’s time to bloom and time to fruit and they mostly do it at the same time, regardless of when you put them in the ground. But most of us can’t wait and plant as soon as possible. Remember too, that the last frost date is an average, so it’s possible to get killing temperatures after that date.
Seeding Trays: The best way to save money is to buy the right equipment. Kitchen foil pans, disposable cups etc. were not designed for seed starting. These Perma-Nest are the absolute best, lasting over 10 years. There are a few sizes of both trays and domes. The tan colored ones seem to be made of a better material than the green.
Moist planting medium: The first thing to do is moisten (moist, not wet) your planting medium. I keep the bulk of it dry, so it doesn’t get moldy. I like a gallon bucket with lid and moisten only the amount I plan to use. If you do this a few hours before, it gives the water time to soak in and you can later add more water or mix, depending on how moist you want it to be. If not pre-moistened, the water just sits on the surface and even when it passes through, your seed might be sitting in a dry spot.
Label, label, label: Except for a few potato-leaf varieties, tomato seedlings all look the same. Make your labels before you even open the seed packet. Stick the label into the mix before you plant, to avoid disturbing the newly planted seed.
Planting depth is usually indicated at 1/8 to ¼ inch. Either fill the mix and poke holes the right depth or place the seeds and top up the mix over it. Better too shallow than too deep. Gently tamp down the surface to have the seed make good contact with the moist mix. Do not water, or the seed will move all over and even float to the surface. Bottom water until roots can hold it in place.
Heat and humidity: It’s possible to get germination in 3 days. I pick the 3 coldest nights and place it on a table, over a radiator. You don’t want them to cook, just to hang out in a steam room. Or you could use a heat mat, like a sane person. I try to avoid the extra carbon footprint and electricity bill. Water sparingly, after leaves start to appear and keep them warm. Cool, wet soil may cause rot.
Light is an important factor as soon as seeds germinate. Without enough light, plants will grow into long stringy vines, tangle, break or become diseased.
Air circulation with a fan provides the wind that plants have outdoors to develop sturdy, strong stems. Air circulation also helps to minimize disease.
Transplant seedlings when they have two pairs of leaves. If you have a few growing together, they tease apart easily, especially if the planting mix was not compressed. A toothpick helps, so you don’t squeeze and pull too hard on the stems. Hold the leaves or stems very gently to avoid bruising. Transplant each into a pot at least 3 inches deep. Fill it up to the brim, make a hole all the way to the bottom, then ease the seedling in until only one pair of leaves remain above soil level. Tomatoes root from all along the stem, so planting them deep will enable a stronger root system to develop. Gently press the mix down to secure the seedling in place and water it in.
Hardening off is the process of acclimatizing them to the outdoors. Toughen them up by putting them outdoors for a few hours a day. They need to adjust to the intensity of the sun and the drying effects of wind. Too much, too soon, and they can scald and dry out. A bit like a person starting a tan.
Most tomato growers will experience some setbacks or disappointment. Just enjoy the ones that do make it and learn from your experience.