This year I have 196 little seedlings growing under lights… lots and lots of tomatoes, a variety of other vegetables, and some herbs. We usually get a killing frost in early June, so I have learned to start my seedlings late so they will be just the right size when it is time to transplant them into the garden. I have a two-tier white metal plant stand that will hold four trays at each level. The stand came with one long fluorescent grow light for each tier. We modified the design slightly to add an additional grow light at each level so the plants near the edges of the trays get as much light as the plants in the middle.
I grow my seedlings in plastic cups. I prefer to use clear plastic cups because it is easier to keep an eye on the plant’s root development… it is very obvious (as in this photo) when the seedling needs to be transplanted into a larger cup. I start with three-ounce cups and move on to larger sizes as necessary, up to the tall 16-ounce size. Cups are especially good for tomato seedlings because the height of the cup provides a lot of soil area for root development. I wash and disinfect the cups at the end of every seedling season and use the same cups year after year. Since I prefer to water seedlings from the bottom, I cut a good-sized hole in the bottom of each cup.
I usually plant seeds directly into the cups, one seed to a cup, and re-plant if necessary. This year I decided I would try planting the extras of the non-hybrid heirloom-type seeds that I had planted in previous years. These seeds were up to eight years old, and I didn’t think many of them would still be viable, so I “planted” the seeds inside a folded piece of dampened paper towel and checked the seeds each day for any sprouting. Much to my surprise, almost every seed produced a sprout. As soon as it was obvious that a seed had sprouted, I immediately planted it in one of the small cups and got it under the lights.
I keep the lights low over the plants at a level of about two inches over the tallest seedling. This works especially well with tomato plants and keeps them from becoming tall and “leggy.” Tomatoes grow amazingly fast, so I check the lights every morning and a couple of times through the day to see if they need to be adjusted.
I will start a few cucumber and squash plants as we get nearer the end of this month. The plastic cups work especially well with these because when it is time to plant the seedlings in the garden, the hole in the bottom of the cup makes it easy to push the soil and plant out of the cup without disturbing the roots. I have never been able to do this as satisfactorily with the plastic plant cells or any other seedling options.
I might have a slightly different attitude during the days we’ll be setting out all of these seedlings… but the rest of the season, I don’t think it’s possible to grow too many tomatoes! We eat them fresh, I make sauce and paste, and freeze or can the extras. And we pack some away so we can have “fresh” tomatoes from our garden late into the fall… perhaps even as late as Christmas day!