The Plant Lady: Tips to help get your vegetable garden started from seed starting now
Yes it’s winter, but believe it or not it is time to start summer vegetables inside. There are multiple reasons to start seeds indoors. One reason is plant variety is greater in seed form than in starter plants offered at nurseries. Starting seeds inside prevents animal predation — snails/slugs, earwigs and birds can do a number on seedlings as they emerge in outdoor beds. And starting seeds inside gives you a jumpstart on the season.
When the weather reaches optimal planting conditions, your plants will be ready to go in the ground. Not all vegetable seeds qualify for starting inside. Many seeds are best directly sown in the ground, such as corn. Tomatoes are usually the first to sow followed by peppers, eggplants, squash and then your watermelons. The UC Davis website has a home gardening guide that explains when to plant common vegetables.
Seed-starting containers can vary. The key is to plant seeds in something deep enough to allow a good root system to establish. I often see a suggestion to plant your seeds in egg shells or egg cartons — those are very shallow and not ideal. Cell packs are an easy way to start many seeds in a small space. These can be found in plastic or in peat moss (biodegradable pressed peat). The peat pot cell packs can be separated and planted directly in the ground. Besides cell packs, seeds can be planted in pretty much any pot with a drain hole, such as individual peat pots, plastic 3-inch nursery pots or even cups.
A dollar store is a great place to shop for inexpensive seed starting cup containers. If you want something environmentally friendly, look for biodegradable paper cups. Be careful with those — if kept too long they can degrade before you are ready to plant them. Red plastic cups work great as starter pots. Regardless of the type of cup, drill a hole in the bottom for drainage.
If starting in a cell pack, it is often necessary to move them into a larger pot (3 to 4 inches deep). Generally, this is done when the plant has its second set of true leaves (the first leaves to emerge are called cotyledons). Always plant a few extras seeds than the goal number of plants, as you want to take into account germination failure. If all seeds do germinate, you can tease them apart and replant in their own individual pots or you can cut out the unwanted seedling.
When growing inside you will need to place the pots in a tray to prevent water from getting everywhere. Nursery trays work, however I find that aluminum roasting pans work better. They are cheap and the sides are higher than nursery trays. Anything works as long as it holds a bit of water.
A seed-starting mix is ideal to plant your seeds in. This is comprised of peat moss (majority) with a bit of perlite for added aeration. The peat moss has excellent water-holding capabilities and allows small roots to adhere to soil, versus a looser potting mix. Most seed-starting mixes also contain a smidgen of fertilizer. The key to working with peat-based soil is to first wet the soil completely before adding to a pot — this prevents dry pockets. Remember to lightly press the soil down into the pot before planting. Read the seed packet to determine how deep it should be planted and if you need to cover the seed.
Make sure to label your plants as well — old mini blinds cut into small strips are ideal as plant labels. Be sure to write with a pencil.
To speed up the process of germination, a heat mat is ideal. They can be found at most nurseries. Heat mats increase the ambient air temperature by roughly 10 to 20 degrees. You can set the heat mat on a timer, but I let mine run constantly until the first or second set of true leaves are produced.
Light is crucial once your seeds germinate. A sunny window (south or east facing) will work, but sometimes this isn’t quite enough light and plants can start stretching and become leggy. This usually isn’t a long-term problem, especially for tomatoes, where you can just bury the long stem. You may also need to rotate your plants if they are stretching and growing towards the light. If you can supplement with a light, then your plants will stay shorter and more compact. A 4-inch fluorescent bar light works well. The key is to place the light only about 8 inches above the plants and move it up as the plants grow. An aquarium full-spectrum LED light will also work.
Keep the soil moist as the plants germinate. As the plants grow and establish a root system, you will need to water more frequently. Also avoid the soil staying too wet. Soggy soil can lead to rot and fungal gnats. You can water from the top, but bottom watering is a good way to prevent soil spillage and hurting tiny seedlings as they emerge. Simply fill the tray with an inch or two of water. Just be sure to not leave water in the tray for longer than a few hours.
When outside temperatures warm up, you can move your seedlings to a sheltered place outside to harden them off for a week or two before you plant them in the garden.
