If you’re planting a garden, you’ll need to decide if you’re planting seeds or seedlings. Here’s what you need to know about seed germination and growing vegetables from seeds.
When starting your garden, you’ll have two options: Planting seeds or transplanting seedlings. There are pros and cons for each, and I suspect you’ll find that most gardeners do a little bit of both. If you opt to start with seedlings for some (or all) of your planting needs, you have two options: Picking them up at the nursery or growing vegetables from seeds yourself.
Benefits of growing vegetables from seeds
- There are so many more varieties to choose from than the standard nursery fare.
- You can get started while it’s still too cold outside to do other gardening projects.
- It’s less expensive.
- You can use seeds saved from last year’s garden, as long as they are an open-pollinated variety.
Benefits of starting with seedlings
- Starting with small plants can help avoid trouble with pests.
- Seedlings will often produce sooner than seeds planted at the same time.
- They’re visible – you’ll know right where they are in the garden.
- If you buy seedlings at the nursery, someone else has done some of the work for you.
Seed Germination 101
Simply put, the process of germination is a seedling sprouting from a seed. Given appropriate conditions, a seed germinates, sends out cotyledon (first leaves), and then matures into a seedling. Germinating seeds is not difficult — so long as you provide sufficient moisture, light, and the proper temperature. These requirements vary by type of vegetable, but it’s safe to say that seeds prefer a bit of warmth to germinate.
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While veggie seeds will germinate in an optimum range, check out the optimum temperatures in the chart below. A heated seed mat is almost always going to boost your success rate if you’re trying to germinate seeds before optimum weather conditions prevail outdoors!
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Planting seeds: Should you pre-sprout?
If you’ve ever planted an envelope full of seeds in soil only to have just a few sprouts emerge, you’ll appreciate the idea of pre-sprouting seeds. With pre-sprouting, you can see in advance which seeds are viable. This is an especially valuable tool if you’ve got old seeds from past seasons. By pre-sprouting, you can see which ones will actually grow in the garden, rather than planting row upon row of seeds that will disappoint.
How to pre-sprout seeds
There are a couple of different ways to do it, but the general idea is to keep seeds moist and warm for a few days so they have a chance to sprout. I’ve experimented with using paper towels, newspaper, and old t-shirts for pre-sprouting seeds. Bar none, I find the t-shirts to work the best since they retain moisture so well.
Soak sections cut from old cotton t-shirts in water. Sprinkle seeds onto the fabric’s surface and fold fabric in half. Roll up and secure. (I used masking tape.) Check daily to make sure the cloth is still moist. (Be sure it’s not over-saturated; this will cause the seeds to rot.) I kept mine in a recycled plastic strawberry container to help retain moisture. As soon as you see the seeds begin to send out sprouts, carefully lift each one and plant in a soil-filled pot.
The tip of a pencil or a knife can work well for moving seeds after they’ve germinated. Don’t allow the sprouted seeds to linger at this stage, or they’ll send little roots into the fabric, making it difficult to move them.
- Read about the benefits of pre-sprouting seeds here.
Growing vegetables from seeds
Why plant seeds in pots? There are a couple of reasons. First, some seeds are just kind of hard to plant directly in the garden. I put tomatoes, peppers, and eggplant in this category. The tender, tiny sprouts tend to be more susceptible to pests when they sprout right in the garden and there’s more loss when they’re planted directly, I find.
I like to set seedlings for these vegetables out in the garden. I could buy those seedlings, or I can start my own. (For years I bought tomato seedlings — it’s what my mom did. Then I tried growing vegetables from seeds, and it turns out, tomatoes are really easy to sprout.)
Secondly, and probably more importantly, planting seeds indoors allows gardeners to beat the seasons. With a little light and warmth, you can start seeds indoors even when there’s snow on the ground. As soon as it’s warm enough outside, you’ll have seedlings to plant out.
Planting seeds indoors requires a fair amount of light and a warm place to germinate. I finally invested in several heated seed mats and an LED light for my seed starting area and I’ve been much more successful with germination this year.
Planting seeds indoors
Start with a good potting soil for good seed germination. I’ve used bagged potting mix and I’ve mixed peat moss with worm castings. There are special seed starting mixes, but I’m not convinced that they’re necessary. No matter what type of medium you choose for germinating your seeds, be sure to wet the material well first. This is especially true of seed starting mixes that are high in peat content. If the medium isn’t wet to begin with, water will pool on top of the soil and won’t penetrate to the roots.
Fill containers with potting soil to within 1″ of the top. (Or use soil blocks.)
Seed packets include planting directions and will note the planting depth suggested for each type of seed. A good general rule when growing vegetables from seeds is to plant a seed twice the depth of its size.
Large seeds like squash and beans will be planted deeper than smaller seeds. Other seeds—tomato, pepper, eggplant—are surface sown or just barely covered with soil. Set a seed or two into the appropriately sized planting hole, cover it with soil, and water it.
Related: Vegetable Planting Guide
You can also plant multiple seeds in a container. I’ll do this if I’m unsure about the viability of my seeds. Once they sprout, the seedlings will need to be carefully separated and planted into individual pots until time to plant them in the garden.
Place your containers in a warm place (or on a heated seed mat that gets plenty of light and wait for the seeds to sprout. If you don’t have a well-lit space, consider adding grow lights to the plan. Once sprouted, keep the soil moist and sing to them while you await your last frost date.
Direct sowing seeds in the garden
Generally speaking, the seeds that do well sown directly in the garden are large seeds, like those of squash, cucumbers, peas, and beans. Maybe it’s my own bias, but I just feel that planting seeds for these veggies leads to sturdy seedlings quickly enough that they can hang tough in the garden.
Root crops like radishes, beets, turnips, and carrots are also good for direct sowing. Some seeds simply dislike being transplanted, so you’ll want to direct sow those. Corn, beans, carrots, peas, and radishes fall in this category. The steps for growing vegetables from seeds in the garden mimic those for planting in containers — you just do it directly in your garden soil.
You can plant your seeds in rows, which has been the garden standard for years, or use a broadcast method when growing vegetables from seed. Just be sure to use garden markers to identify what you’ve planted where. And consider soaking your seeds for an improved germination rate.
- Here are 13 easy vegetables to direct sow.
To plant in rows:
Make a furrow for the seeds at the appropriate depth. Sow seeds spaced evenly at the distance suggested on the seed packet. You’ll be able to manually place large seeds. Smaller seeds are a little harder to get exact, and that’s okay.
If you notice that the sprouts are too thick anywhere, you can thin out once the seedlings have two true sets of leaves. The plants that you thin out are what many farmers markets sell as “baby greens” — be sure to save them for adding to salads!
Small seeds do well with this method. Determine the area that you’ll be planting. Rake to loosen the soil surface, then scatter seeds as evenly as possible. Lightly rake again, then spread a thin layer of sifted compost over the area.
- If you’re tight on space, try your hand at Square Foot Gardening.
Use a fine mist to moisten the newly planted area. You’ll need to maintain that moisture until seedlings sprout; on hot days, you may need to water more than once.
Originally published March, 2016.