Seed Starting Success
If you’ve never grown your own seedlings, or tried and failed, check out these tips before you get started!
Indoor seeding tips
Clean trays or pots thoroughly if you reuse them from last year. Some gardeners add a tiny bit of bleach or hydrogen peroxide (29%) to rinsing water as a disinfectant.
Plant one crop per tray/pot, or combine crops that grow at a similar speed (e.g. peppers germinate much more slowly than tomatoes).
Cover trays with dome lids or other transparent lids to keep the soil surface moist. Don’t let too much moisture collect inside - lift daily to allow air circulation. Take lids off as soon as seeds germinate.
A heat mat underneath the pots will speed up germination. After germination, don’t keep seedlings on the heat mat (except eggplant).
Without proper lighting the seedlings stretch and become leggy, thin and flimsy. A West-facing or South-facing window can provide enough light. A grow light helps in places with less sun. The grow light should be low down, very close to the plants.
Some gardeners prefer to germinate seeds before planting them into soil. I skip this step, but if you’d like to, here’s how: place seeds on a wet paper towel inside a sealed bag. Warmth speeds up the process. After germination carefully transfer them one by one into their pots.
Watch out for damping off and fungus gnats.
Hardening off - an essential step
Seedlings started inside need to adjust gradually to outdoor conditions, otherwise they will be damaged or killed by the shock. Harden them off by exposing to air and light a little bit at a time. First take them outside for less than half a day in a sheltered shady location. Don’t expose them to direct sun or high winds right away! The next time, leave them outside longer. Keep gradually increasing the time that the plants are outside. Finally leave overnight in their pots before transplanting out into the garden. On the hot sunny days, cover plants with row cover (or a thin light cloth) when they first go out, because baby plants can get sunburn.
Gardening calendar made simple
Scroll down to the end of the post for a more detailed, crop-by-crop seeding calendar.
Mid / Late March
Indoor seeding: tomatoes, peppers, herbs (basil, parsley, shiso, marigolds), perennial herbs.
Purchase soil, mulch, any supplies.
Prepare row covers or cold frames outdoors.
Early April
Indoor seeding: tomatoes, tomatillos, ground cherries, huckleberries, herbs, flowers.
Outdoor seeding under cold frames or row covers: peas, fava beans, cold weather greens e.g. lettuce & spinach, orach, Cabbage-family crops. I have seeded peas under covers as early as late March.
Outdoor work: (weather-dependent):
Begin to prepare the pots. If re-using last year’s soil, add some more compost or manure.
Prune perennial shrubs, vines, trees. This should be done while plants are dormant. Some are better to prune right after fruiting. It varies for individual plants.
April
Indoor potting-up: (usually peppers, eggplant and other annuals that were seeded indoors in March need to be transferred from trays to 4-inch/6-inch pots at this time)
Late April, as soon as the ground can be worked
Outdoor seeding: cold weather greens (lettuce, spinach, cilantro, cabbage-family plants such as arugula, kale, bok choi, pak choi, mustard), peas, fava beans.
Transplants: native plants and other perennials, shrubs, berries, flowers.
May
Hardening off (weather-dependent) seedlings on warm days.
Indoor seeding: long-season cucumbers, okra.
Indoor potting-up.
Outdoor seeding: salad greens.
Transplants: native plants and other perennials.
Late May
Transplants: (weather-dependent): annuals such as tomatoes, ground cherries, marigolds, herbs, flowers.
Outdoor seeding: direct-seeded herbs, greens and root crops, molokhiya, amaranth.
Last week: transplant peppers.
Prepare/build trellis and vertical support, if neccessary for climbing plants.
Seed starting chart for 52 balcony plants
Includes first and last seeding dates, spacing and pot size, indoor and outdoor seeding, all in a handy 2-page chart filled with balcony garden plants!
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