by Eliza Holcombe Lord, Master Gardener, Master Naturalist, PermaculturistUpdate: We’ve recently created three FREE video classes and an ebook that will teach you everything you need to know to grow your own garden plants from seed. After you read this article, go check them out here!
Tip: Top 4 Problems New Seed Growers Face & What To Do About Them
If you’ve tried starting plants from seed (e.g. “seed starting”) before and failed, don’t worry! You’re in good company. Nurseryman Tony Avent says, “You don’t know a plant until you’ve killed it 3 times.”
So you can look at those early attempts as lessons teaching you that baby plants need lots of bright light and dislike extremes in water or temperature.
Top 4 problems new seed growers face:
1: Not enough warmth
Be sure to find out what temperature seeds need in order to germinate. There is a wide degree of variation. For example: tomato seeds germinate best between 70-80 °F, mâche prefers 50-60 °F, watermelons 70-95 °F, etc., so if you tried to start all these seeds at the same temperature, you’d get vastly different germination results. When starting warm-loving seeds indoors, place seed trays in a warm spot. For instance, higher in a room such as the top of a refrigerator or you can use a heating mat and thermostat controller like we do. Fast-germinating seeds are less likely to rot. As soon as you see the seedlings peeking above the surface, move them to your light source, which brings us to our next point…
2. Not enough light.
Nearly all seedlings need 6 or more hours of bright-as-the-sun light per day. If you want to use a windowsill, make sure you have a non-shaded, south or southeast facing window. If you don’t, purchase grow lights or plan to take your germinated seedlings outside when temperatures are above 50 °F. You can tell your seedlings are not getting enough light if their leaves look yellow and/or they look “leggy,” e.g. very long stems (this is the seedlings way of trying desperately to reach more sunlight).
3. Extremes in temperature and/or moisture.
Few seedlings appreciate cold and soggy or hot and dry soil — for most seeds (especially spring & summer varieties), aim for around 68-75 °F and moisture levels that feel like a well wrung-out sponge. Never let seed trays sit in standing water for longer than 10 minutes.
4. Too much or too little humidity.
In dry climates it’s a good idea to use a plastic dome or plastic wrap to keep pots moist, but this should be removed as soon as the seedlings pop above the soil surface. In humid regions the domes often hold too much moisture next to the soil and can cause mold or disease, such as “damping off” where seemingly healthy seedlings can wilt and die overnight.