You can use darned near anything for seedling containers. I’ve seen people use the classic terracotta or plastic nursery pots, yogurt and cottage cheese containers, old plastic milk jugs, styrofoam cups, plastic seedling trays, newspaper pots and wooden seedling flats. I use tin cans that I or other people have saved. I use cans for several reasons.
- They’re free if you get them from other people, or they’re a leftover from stuff you buy in cans. Even when you preserve most of your own food, there may still be things you want to buy in cans, like olives.
- They’re reusable for a long time. Eventually, the bottoms of the cans rust out completely (for that matter, so does the entire can), but most last close to 10 years.
- They don’t have to be carefully stacked or stored to prevent crushing or breakage and can be stored outside, even in full sun.
- They’re an easy size to handle and lightweight enough to fill with soil and still pick up 10 to 20 cans in a carrier such as an old jelly-roll pan (which I can find at yard sales).
- It’s easier to dig a round hole and tamp dirt in after planting than it is with a square hole.
- Since each plant has its own container, you’re not damaging roots as you do when you cut individual plants out of flats with all the seedlings growing side by side. I typically plant several seeds in each can and thin to the most vigorous seedling. Germination rates vary, especially if you’re using older seed. I plant three seeds for seed that is up to three years old, as the germination rate is typically at least 70 percent. If the seed is older, or notoriously hard to germinate, I may plant up to five big seeds or 10 small seeds. I space them far enough apart to make it easy to thin what I don’t want, but try to keep them in the center of the can so the best one has plenty of growing room. I don’t generally transplant until I’m ready to put them in the garden. My plants rarely suffer transplant shock. I water the seedling and the hole well, tap around the sides of the can with a trowel and then give the bottom a couple of good sharp taps. The plant almost always slides right out with the root ball intact. In most cases, the soil in the can is pretty well filled with roots. Once I tamp the soil around it and water again to settle the soil, those roots quickly spread into the surrounding soil. Because there’s so little root disturbance with this method, I can transplant stuff that usually doesn’t like being moved, such as cucurbits and corn.
- The cans are big enough that if weather or workload delays me, they’ve got growing room for an additional week or two.
- Can sizes vary. My daughter has a lot of #10 cans from the store’s pizza-making activities – they hold about a half-gallon of soil. I also use the cans in which we buy coffee; they hold about two and a half cups of soil. These cans have a rim around the top, which means it’s harder to get the transplants out. I turn them upside down and cut out the bottom. Since they are sitting on a solid surface, the soil stays in the can. For these, I don’t need to worry about drainage holes. For the other cans, I punch four to eight drainage holes in the bottom, depending on the size of the can, and fill with a mix of compost and soil. I don’t clean them or use sterilized soils, and I have no problems with damping off or other plant diseases. The #10 cans are big enough that I can use them to expand my growing space.
Starting plants for transplanting rather than direct seeding is important for several reasons.
- Succession planting is highly reliant on transplants, especially in short season areas or if you have limited space. You need to allow a window on your harvesting date, as it may take more or less time (a two-week window is usually about right). Instead of waiting to direct seed and messing up your succession schedule, early planting allows you to tuck in your transplants as soon as the first crop comes out. With dryland gardening, Steve Solomon says direct seeding works better. However, Nita Wilton uses both transplants and direct seeding in her dryland garden.
- Starting early allows you to avoid cross-pollination of wind-pollinated plants like corn and still harvest a good crop. Say you have two different corn varieties with 90-day maturity rates. If you direct-seed them together, they’ll be tasseling at the same time and will cross-pollinate. With corn this matters even if you don’t want to save the seed, which I do. If one is a sweet corn and one is a dent or flint corn, it can really affect the quality of the sweet corn for fresh eating. Start one corn as transplants about three weeks before you direct-seed the other one. You should have a large enough window to avoid cross-pollination.
- An early start allows you to start harvesting earlier, which is always nice for us seasonal eaters. When it’s been a most of a year since the last one, you really want to taste that first ripe tomato.
- Insects are tuned to the natural cycles of the garden. So if you direct seed at the usual planting time in your area, that may make it easier for the little buggers to chomp their way through your young, tender plantings. If your plants are a month ahead of the insects, they’re usually well-grown enough to handle a little chewing.
- I think one of the most important early-start reasons for me is that I want plants like tomatoes, peppers and eggplants blossoming and ripening fruits before it gets too hot. Solanum blossoms are notoriously heat-sensitive. Once the temps hit 85 or so, especially if night-time temps are also elevated, the pollen starts dying. In an arid climate like mine, the pollen may also get too dry to be effective. Many heirlooms are even more susceptible to high temperatures than hybrids and I grow only heirlooms. For example, I want my tomatoes old enough to be blossoming by the middle of June. Around here, the really high temperatures start to hit in early to mid-July and continue through most of August. If I start tomatoes early enough, I can have them blossoming before it gets too hot. High temps also affect ripening. Fruits usually ripen about 30 days after blossoming, but again, if it’s too hot, the plants will either hold off on ripening or ripen only to orange instead of red. Once the fruits have set, there are strategies to manage a heat spell. I can either shade, mulch and water them enough to cool things down for ripening, or I can bring in the ones that have started to color and ripen them indoors.
- It’s hard to talk about season extension without mentioning the greenhouse. A greenhouse allows for season extension on both ends. I don’t start my plants under lights, but an unheated greenhouse keeps them from getting clobbered by late frosts in the spring. You can also start some late crops of tomatoes, cukes and such in big pots and grow them in the greenhouse until the hard frosts shut things down.