Starting Plants Indoors

hands starting seeds indoors in a plastic planter tray

Seasoned gardeners know that the best gardens are started inside, well before any signs of spring come along. Whether you're a beginner or a veteran looking for some tips, this article will go over what you need for starting seeds indoors. That way, when the ground is workable, you’ll be ready!

Starting Seeds vs. Buying Seedlings

You can easily buy already-germinated seedlings from your garden center once spring and summer arrive, however, if you germinate your own seeds you can save a ton of money depending on your prospective garden. You’ll pay around $3-5 for small plants at the garden center. That all adds up if you want to plant even a small-sized garden. Plus, if you germinate your own you can control their environment from the very beginning, and make sure they are raised happy and healthy.

Types of Seeds

Even though there are a lot elements that go into making a healthy fruit or vegetable, not all seeds are the same quality. Heritage or heirloom varieties are heralded as the cream of the crop, but can sometimes be expensive, or hard to obtain. Often, you can find good quality seeds online or through local suppliers in your area. Large garden stores will sell packets, as well, but the majority of them will be cheaper, low quality varieties. Just know the difference, and make the choice that’s right for you.

two kinds of seeds on a wooden table with paper packets

When to Start

As a general rule, it’s best to start seeds 4-6 weeks before your region’s last frost date. This will give gardeners who live in four-season climates a big head-start on their garden—or, it can give another round of seedlings for those who want to rotate crops, or double their harvest in warmer climates. The reason for starting seeds indoors depends on region, but most of the time it’s for gardeners wanting to utilize the cooler months leading up to spring planting. If you don’t know your region’s last frost date, you can find this info in the Farmer’s almanac.

Different Start Times

If you're planning a wide variety of plants that require different planting times, do some research as to what you'd like to sow, then organize which seeds should be started first. Things like lettuce, spinach, snow peas, kale, and broccoli can all handle a bit of frost or cooler temps, so you may want to start those seeds earlier. Other veggies like tomatoes and peppers will not tolerate any frost—delaying their start time a bit will ensure they are ready in time with the warmer spring temps. Try starting seeds in batches according to plant times so you have a section that’s ready as the varying temps allow.

Choose Your Method

There are a variety of options for starting seeds, but essentially the process is the same: a few seeds are placed into a small container of dirt, and allowed time to germinate. Peat pellets are compressed blocks of soil that have all the essential nutrients that plants need to germinate. They take some of the mess out of this project, and can be transplanted directly into a bigger pot once the seed has germinated. You can also use small plastic containers or seed flats, which are sold in many different varieties. For best results, place all seed containers in a plastic tray and cover while they germinate.

Soil Types

For germinating seeds, a good quality potting mix or seed starting mix is what you are after (if you aren’t using the peat pellets which are already filled). These light and fluffy mixes aren’t actually considered soil at all, and are mainly composed of perlite, peat moss, and various kinds of bark. As much as you may want to utilize dirt you already own, or buy it cheap at the store, don't use garden soil—it's too compacted and stripped of nutrients, so it won't help your seeds do their best.

Seed Depth

Seed packets will tell you how deep you need to sow each seed, and there are definitely some variations, so stick closely to this information. Drop two to three seeds into each pellet or container and then cover the soil back up around them. Why not just one seed, you ask? Not every seed will germinate no matter how great the conditions are, so this ensures at least one will sprout. If you happen to get three that pop up, you can “thin them out,” or pinch away the two that are weakest right at the soil line.

Label Your Seeds

If you have ever forgotten this step, you’ll know that almost every seedling looks the same once they sprout! To save yourself from trying to determine which kind of basil is which, find a system for labeling your pellets or containers as you fill them. This can be as easy as writing plant names on tiny strips of paper and applying them to containers with some tape.

seedlings starting in small pots in a city apartment

Light and Water Requirements

When the seeds are in the germination stage, they don’t require a high amount of light, but they will require warmth. They also want to remain moist so keep an eye on the color of the dirt—you should be able to tell if it's dried because it will be a lighter brown. Take the cover off of your tray and add some water to the bottom, just enough so that the pellets or containers can draw water. Don't over-water or saturate, but try and keep conditions consistently warm and moist.

Once They Germinate

Once your seeds have all produced a tiny green sprout, allow yourself to celebrate! Then, remove the plastic cover from the tray and move them to a bright area kept at room temperature. Most seedlings will get enough light from a large, sunny, south-facing window; however, a lot of people opt to supplement or only use grow lights.

Seedlings will get “leggy” if there is not enough light, and some may simply become too weak to keep growing. Once they have two pairs of leaves, they will need to be transplanted into their next container and allowed to grow a bit more before being moved outside. Fill with potting mix and water as needed.

There are many benefits to starting your seeds indoors, and most people can do it themselves without any previous gardening experience. Save yourself time and money by following these steps, and enjoy the extra reward of knowing you were with your plant babies right from the start.