Starting seeds indoors — the setup — print version.
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SUS Farms · Utah Gardening
Starting seeds indoors — the setup
season · beginner · ~6 min read
Starting your own transplants is the cheapest way to get exactly the varieties you want. The 80% of seed starts that fail come from one of three setup mistakes: not enough light, wrong temperature, or watering from the top.
Light first, everything else second
A windowsill is not enough light. You need a shop light or LED grow light 2–4" above the seedlings, on for 14–16 hours a day. Without dedicated light, seedlings stretch and fall over within a week of germination.
Bottom heat for germination
Most warm-season crops germinate at 70–90°F. A seedling heat mat under the tray ($25) doubles or triples germination rates. Once seeds sprout, MOVE THEM OFF THE HEAT — heat stress is the second most common failure point.
Bottom-water, never top-water
Pour water into the tray (not on the soil) and let the cells absorb up. Top-watering compacts soil, washes seeds out, and spreads damping-off fungus. A 1018 tray with no holes makes this trivial.
Hardening-off is mandatory
A week before transplant, start putting plants outside in shade for an hour. Add an hour and more sun each day. Skip if windy or below 50°F. Plants that go from indoor LED to outdoor sun without this transition burn and die.