It’s never too early, or is it?
You couldn’t wait, could you? You started seeds in February, even January, and soon you won’t be able see out of the window for tomato plants, or your grow lights are shaded out by pepper plants and geraniums. You’re not alone; I’ve done it.
But when to plant seeds indoors? The answer is to check the instructions on the seed packets and wait. When it says start six weeks before my last frost (May19, more or less) it means I shouldn’t start them until April 6 — still another three weeks. That’s a long winter of anticipation. I imagine my fellow gardeners are much more sensible than I am and are able to restrain themselves from being too hasty, or they, too, already have trays of seedlings on the go. For those who waited, here are a few tips and reminders.
Seed trays are widely available, but almost anything that can hold a couple of inches of soil and has drainage holes in the bottom will do. All containers will need a plastic cover to keep up the humidity level. Blue boxes on collection day are an excellent source. If you can match a plastic cake cover up with a pot the same size you’ll have the perfect propagation chambers, or you can slip a large cover over a number of individual pots. Covers should not be totally airtight and must be removed as soon as germination occurs.
Fill the containers with a lightweight, soil-free mix. These mixes are usually made up of peat moss with vermiculite and perlite added, although there is a move away from peat because of the environmental impact of harvesting it. Regular potting soil is a little too heavy although it will work. Old-time gardeners were starting seeds in regular garden soil long before there was anything else available.
Sowing depth is important if you want to be sure seeds germinate. One reason they don’t is because they’re planted too deeply. In fact, some seeds need only be scattered on the surface. A tiny seed, germinating too far down, will use up its food store before it ever reaches the light, where it can begin making its own food. Follow the instructions on the seed packet closely. If there are none, or you’ve lost the packet, plant seeds at varying depths to be sure some germinate.
Some gardeners like to use the baggie method to germinate the seeds before planting, and it’s a good way to determine if old seeds are still viable. Spread the seeds on one half of a paper towel then fold the towel over the seeds. Next, spritz with water then place the moistened paper towel in a plastic bag. Seal the bag and place it wherever you feel the temperature is suitable for the particular seeds. Some have preferred temperatures for germination, but room temperature is generally OK.
As for light, the seeds of calendula, gazania, delphinium, pansy and verbena are typical of those that prefer to be left in the dark until they germinate, but check daily because they will need light as soon as they do pop up. Some species, such as begonias, geraniums and petunias, require light to germinate, and covering them with soil will inhibit their sprouting.
Starting seeds on a windowsill is fine, but never in full sun. A container with a clear plastic cover placed in full sun will get hot enough to poach an egg. A south facing window with sheer curtains is as good as you can get. Otherwise, a grow light or a simple LED shop light gives much better control.
There’s tons more to starting seeds, but if you follow these basic instructions you’ll be successful, maybe even too successful. What, you started your tomatoes back in January?
DAVID HOBSON CAN BE REACHED AT GARDEN@GTO.NET. VIEW HIS IMAGES @ROOT46 ON INSTAGRAM. TO CHAT WITH LOCAL GARDENERS AND SHARE TIPS AND PHOTOS, SEE GRAND GARDENERS ON FACEBOOK AT FACEBOOK.COM/GROUPS/GRANDGARDENERS/.