A Gardening Editor’s Seven Tips for Starting Seeds

One of my favorite first gardening books was A Garden from A Hundred Packets of Seed by James Fenton. I remember being enthralled by the idea that a young, poor gardener like myself could afford to have a big, beautiful flower garden, simply by opening a few (or many) packets of seed and buying a bag of potting mix. It opened my mind to the idea that my garden offered more possibilities than my thin wallet might otherwise suggest.

My sense is that, in these heady days of COVID-19, many people feel the same way about starting vegetables. It’s hard not to look through all the seed catalogues that arrived in December and think of all the food you could grow for your family, if you just had a few (or many) packets of seed. The promise isn’t just one of future meals, but also a dream of self-sufficiency. If the rest of the world runs out of food, you’ll still have your vegetable garden!

Your dream, however, relies on getting those seeds to become healthy, productive plants. There is hope in a seed, but there can also be tragedy and despair. Following these guidelines for starting seeds indoors will help you avoid at least some of the heartbreak.

Get a clean start. “Damping-off,” a fungus that attacks young seedlings, is the bane of every seed-starter at some point. You can reduce your risk by washing all of your seed-starting trays and containers with hot, soapy water and by starting with a fresh bag of germinating mix.

Plant at the right depth. A good rule to follow when starting seeds is to plant a seed at a depth that amounts to no more than two-and-a-half times its width. When in doubt, err on the side of planting shallowly. If you plant a seed too deeply, it will run out of energy before the young sprout can reach the light and start photosynthesizing.

Keep the soil moist. Seeds need water to germinate, so keep your freshly planted tray covered with a bit of plastic to keep the moisture in. After your seedlings sprout, remove the plastic and water seeds as often as necessary to keep the planting mix damp but not soggy. Your tray should drain freely.

Speed it up with heat. Giving your seeds some bottom heat will speed up your germination mightily. A seedling heat mat is ideal, but simply putting trays in the warmest part of your house will help.

Give them light. A sunny, south-facing window may be enough to give your seedlings the light they need, but you’ll have even better results if you set up a simple fluorescent shop light. Hang it low enough so that the lights are just a couple of inches away from the seedlings.

Give them time. When it comes time to transition your plants to the garden, do it slowly to avoid shocking your tender seedlings with too much light, wind, and temperature variation all at once. Start by putting them out in the shade for just a couple of hours, then slowly increase the amount of time outdoors and the amount of exposure over the course of a week.

Know your last-frost date. Use a website like this one to find the average date of the last spring frost for your area. If you’re growing tender plants like tomatoes, you’ll want to plant them outside only when you’re sure they won’t get hit by frost.