Two more weeks and it's officially Spring! I started my impatiens today, and thought a quick blog post on seed-starting tricks might be fun.
1. Use a plastic bag to wet the soil.
My friend Beth taught me this trick. Dry potting mix, especially the fine seed-starting mixes, are hard to wet. Just place the needed amount of soil mix in a zip-lock storage bag, add warm water, and zip it up, squeezing out the air. Then squish the water through. Then put the wet potting mix in your planting containers. Works much better!
For what it's worth, I rarely use the fine seed-starting mixes. I just start seeds in the same potting mix I use for everything.
2. Plant in plastic containers.
Plastic is washable, and can be re-used for years. All sorts of plastic containers can be turned into seed-starting containers by adding drainage holes to the bottom. I use a soldering iron to melt holes. Those plastic trays from frozen dinner entrees make great seedling flats. For bigger seedlings, like peppers and tomatoes, I have a stack of plastic pots that came with plants bought at garden centers – endlessly reusable and dishwasher-safe.
But if you're growing a lot of seedlings, space management is key. I invested in a couple seedling trays like the one above, and 6-pack inserts. They're cheap and washable. They sell different sizes of 6-pack and 8-pack inserts. I just use the 48-cell size – 8 6-packs per tray. The cells are big enough for annuals like pansies and impatiens. Two trays fit perfectly under a 48” fluorescent shop light. (Seed trays at Park Seed.)
My book, Indoor Salad: How to Grow Vegetables Indoors, explains how to make a simple seedling light shelf with a 48” fluorescent shoplight. It's easy and inexpensive.
I tried making clever little newspaper pots once. Never again. It's easier to handle 6-packs than 6 times as many little pots, and they got moldy. Seedlings die of illness, and mold smells bad and makes me sick, too. I prefer fresh-washed, clean plastic. In the picture above, there are some recycled paper pots. That was a mistake. They smell. Dixie cups are OK if the seedling is only going to be in it for a couple weeks. Longer than that, and I prefer plastic.
3. Plant seeds indoors.
You can direct-sow some seeds. And there are a few seeds that grow best that way, like beans and cucumbers after the soil is warm. But other than that, it's better to start seeds indoors and transplant them out when they need space. Even if you're starting replacement plants outdoors, like a second crop of lettuce, use a 6-pack rather than wasting prime garden or container space on seedlings. A container of seedlings looks mighty barren.