Commencing Indoor Seeding at Optimal Times for a Thriving Garden
Navigating when to plant your preferred blooms, herbs, and veggies indoors can appear overwhelming, given that some seeds demand an early planting compared to others. Yet, regardless of your seed selection or growing zone, this seed starting manual caters to your needs. Below, you'll uncover the optimal seeds to sow indoors and comprehend the specific timing for planting your favorite seeds indoors and subsequently moving seedlings outside into your garden.
Seeds to Sow Indoors
Several seeds thrive with direct sowing in the garden, while others prefer an indoor start, which can be later transplanted outdoors. Indoor sowing is generally optimal for slow-growing seeds requiring ample time to mature prior to the harvest season or heat-loving plants that won't tolerate cool spring weather.
While various types of seeds can be sown indoors, the following plants particularly excel:
- Nightshades, including peppers, eggplants, and tomatoes.
- Brassicas, including broccoli, cauliflower, and cabbage.
- Alliums, including onions, shallots, and leeks.
- Numerous perennial and annual flowers, including marigolds and snapdragons.
- Many herbs, including basil and lavender.
- Okra
- Celery
- Artichokes
Seeds Not to Sow Indoors
Although the majority of common vegetable, flower, and vegetable seeds can be sown indoors, there are a few exceptions. Plants with vining stems or long taproots can be tricky to transplant, while other plants dislike having their roots disturbed after planting.
When planning your year's planting schedule, be mindful that the following plants usually perform better when planted directly outdoors in spring:
- Cucurbits, including cucumbers, melons, and squash.
- Root crops, including carrots, turnips, and beets.
- Fast-growing vegetables, like lettuce, arugula, spinach, kale, and radishes.
- Vining vegetables and flowers, like beans, peas, moonflowers, and morning glories.
- Corn
- Sunflowers
Planting Schedule
Most seeds are sown indoors about 6 to 8 weeks prior to the last frost date of spring. Scheduling, however, varies depending on your region's frost date and the specific seeds you plan to cultivate.
Before you start planting, familiarize yourself with your last frost date and read your seed packets carefully. Seed packets often contain valuable details such as planting instructions and “Days to Harvest” information, allowing you to calculate the optimal time to plant seeds relative to the last frost date.
If your seed packets fail to provide planting instructions, consider the following general planting schedule for common flower, herb, and vegetable seeds:
Mid-Winter
An excellent time to sow slow-growing seeds, such as onions, shallots, and artichokes, is the heart of winter. Additionally, this is the perfect moment to cold stratify wildflower and native plant seeds that require exposure to a cold, damp environment for several weeks before planting. Plants native to cool climatic zones, like boneset and milkweed, exhibit the best germination rates when their seeds are cold stratified around January to February.
8 to 10 Weeks Before Last Frost
Celery, leeks, eggplants, peppers, and flowers such as snapdragons also grow slowly. Sowing these plants 8 to 10 weeks prior to your last spring frost date will ensure they're prepared for transplantation when spring arrives.
6 to 8 Weeks Before Last Frost
Most indoor sowing occurs around 6 to 8 weeks before your last frost date. This is typically when tomato seeds are started indoors, but it's also the ideal period for planting tomatoes, tomatillos, ground cherries, basil, marigolds, and your spring brassica crop. If you've been cold stratifying wildflower seeds, this is the time to relocate those stratified seeds into soil.
4 to 6 Weeks Before Last Frost
As this point in the growing season approaches, you may be able to directly plant cold-hardy crops, such as radishes, in your garden. However, indoor sowing is still recommended for plants sensitive to cold weather. To this end, consider sowing fast-growing crops and certain annuals, such as okra and zinnias, indoors.
Summer
Many gardeners neglect starting seeds indoors during summer, assuming warm summer weather is perfect for sowing seeds outdoors. Nonetheless, cold weather crops have difficulty germinating when they are planted outdoors in hot weather. If you desire your late-summer garden to flourish with cold-tolerant produce, start your fall crop of brassicas and other cold-tolerant vegetables indoors before the end of summer.
Transplanting Seedlings Outdoors
Perfecting your indoor planting schedule is essential. Yet, seedlings started indoors will eventually require transfer to your garden.
Most vegetable, herb, and flower seeds can be transplanted outside after the last spring frost date, once the seedlings are several inches tall and possess sturdy stems and multiple sets of true leaves. However, heat-loving plants, such as tomatoes, should not be transplanted outdoors until temperatures consistently reach above 55°F. Furthermore, remember to hardening seeds off gently for 1 to 2 weeks prior to transplanting, avoiding issues like transplant shock.
- Can it be premature to sow seeds indoors? Absolutely! Sowing seeds indoors too soon might result in your plants growing bigger than your grow room can handle, resulting in unruly and fragile stems that make transplanting a hassle.
- What transpires if seeds are sown too late? If seeds are sown too late, they might not have sufficient time to reach maturity before the harvest season. This might lower your crop yield and leave you unhappy with your harvest.
- Is it genuinely necessary to sow seeds indoors? Although not all seeds necessitate indoor sowing, it's advisable for numerous common plants. Indoor sowing extends your growing season, saves you from purchasing pricy transplants, and enables you to cultivate a wider range of plants that may not be readily available at your local nursery.
Was this information helpful? Kindly share your thoughts! Tell us why!
Sowing seeds indoors is beneficial for slow-growing plants and heat-loving plants that require ample time to mature or can't tolerate cool spring weather. Some examples of seeds that thrive with indoor sowing include nightshades, brassicas, alliums, certain flowers, herbs, okra, celery, and artichokes. On the other hand, vegetables with vining stems or long taproots, fast-growing vegetables, vining vegetables and flowers, and corn are usually best sown directly outdoors in spring, according to Better Homes and Gardens.
