Seed Starting Supplies: Everything You Need to Extend Your Growing Season

January 2, 2023

Starting seeds indoors is a rewarding gardening experience and can help extend the growing season of your garden. It also allows you to include more plant varieties than your typical outdoor growing season may allow. Whether you’re growing for the first time or are looking for tips to improve your setup, check out our guide on the seed starting supplies and knowledge you’ll need to get started.

How to Start Seeds Indoors

Seeds are generally hardy and easy to grow. However, to start seeds that will grow into healthy, vibrant plants, you’ll need a few seed starting supplies.

Time

First, you’ll need time and a little patience. In general, seeds should be started 4-6 weeks before their recommended planting time (keep reading for specific timeframes for each plant type). This will help them grow large and strong enough to withstand the stresses of transplanting.

Planting Space

You’ll also need somewhere to start your seedlings. You can use small seed starter pots, seed starting trays, or even an empty egg carton. Your seedlings won’t need very much room in the beginning, but plan ahead if you don’t want to transplant mid-way through your indoor growing season.

Soil

The best soil for starting seeds is a sterile growing mix which is light enough to allow for rich root growth. Sow the seeds thinly, with ½ an inch between each plant. Then, cover the seeds lightly with a layer of sphagnum peat moss.

Water

Water your seeds with a fine spray or a light drizzle, but do not soak them. While they do need water, they also need oxygen to germinate. If you overwater your seeds, they will drown and fail to sprout.

Warmth and Humidity

If you’re willing to invest a bit more in your seed starting supplies, purchase some clear plastic to cover your seedlings. This will help increase the humidity and keep in moisture. Place your container in a warm spot between 70 and 80 degrees Fahrenheit and watch daily for the seeds to germinate. Not sure where to start your seeds? Try the top of your refrigerator!

Sunlight

Late winter sunlight is sometimes not enough to produce strong, full seedlings. When the first few seeds begin to sprout, move the seedlings to an area that gets bright light for a few hours each day. Daytime temperatures should range from 70-75 degrees, while nighttime temperatures should range from 60-65 degrees.

If you can’t find a sunny spot, you can also substitute sunlight with artificial tube lights placed 2-3” from the tops of your seedlings.

How Do I Care for My Seedlings?

Now that you’ve gotten your seeds to germinate, you’ll need a few additional seed starting supplies to keep them thriving until they can be planted outside.

Fertilize Biweekly

Once your seedlings have developed their first true set of leaves, start fertilizing with half-strength water-soluble fertilizer added into their water. Our favorite seedling fertilizers are organic fish emulsion and seaweed fertilizer. Repeat every other week for strong, full seedlings.

Thin & Transplant Seedlings

As your plants continue to grow, some will look healthier than others. Don’t be afraid to remove seedlings that are thin and leggy in order to make room for those that are thriving.

Thinning out your seedlings and transplanting them will help grow strong plants.

As your seedlings grow larger, you may also need to transplant them into more spacious containers to encourage their growth. Gently repot them and water directly after transplanting. Then, keep your seedlings out of bright sunlight for a few days to help them recover from the stress of transplanting.

Harden Your Seedlings

You may be anxious to get your plants outside, but be sure to harden them off first! Keep an eye on the weather for a cloudy day with even temperatures about a week before your planting date. Take your seedlings outdoors during the day and bring them in at night if frost is possible.

Gradually expose your seedlings to lower temperatures and brighter sunlight over the next week or so before planting. You can also use hotcaps or frost blankets to cover early plantings and help your seedlings harden off and adjust to their new outdoor environment.

Plant Your Seedlings Outdoors

Once the safe planting day for your seedlings has arrived (more on timing below), choose an overcast day for transplanting. Pack the soil around your transplant and try not to disturb the roots. Water your plants lightly after transplanting, and keep the soil moist until the plants are established in their new environment.

When to Start Seeds Indoors

In addition to buying the right seed starting supplies, you’ll also need to keep an eye on the weather and your calendar. The exact dates you should start your seeds will vary depending on your local growing season, your zone, and the plant varieties you choose. Here are general dates to follow for the most popular kinds of produce.

Vegetable Seed Starting Dates

February – Asparagus, celery, onion
March 1 – Broccoli, Brussels sprouts, cabbage, cauliflower, collards, kale, lettuce
March 15 – Eggplant, peppers, tomatoes
April 1 – Summer squash
April 15 – Cantaloupes, cucumbers, winter squash

Flower Seed Starting Dates

January/February – Begonia, carnation, geranium, impatiens, nicotiana, pansy, rudbeckia, salvia, snapdragon, verbena, vinca
March 1 – Ageratum, dahlia, dianthus, petunia
April 15 – Aster, calendula, celosia, marigold, zinnia

Seed starting dates aren’t a science, but you can use them as a general guide to ensure your seeds have enough time to reach their full harvest potential before the weather turns in autumn.

Lettuce plants grown from seeds and thriving in a garden.

If you want to lengthen your harvest, you can also consider staggering your seed starting over the course of several days or weeks. This will help you spread out your largest harvests and keep your vegetables and flowers growing even longer. Once you have a few years of seed starting under your belt, you’ll have a better idea of when to start your seeds in your area to ensure a rich, long harvest season.

When Should You Transplant Your Seedlings?

Your planting date will also depend on your local environment, zone, and varieties of plants. The most important thing is to make sure you transplant your seedlings outside after the last frost of the year. While some hardy plants can survive, it’s always best to avoid freezing conditions.

Plants grown from seed starting trays will thrive outside.

You’ll also want to make sure your plants have grown large enough to thrive outside before you transplant. As a general rule, your plants should have 2-3 sets of leaves before you begin to harden them off and transplant them outside.

Choosing Your Seeds

One of the most important seed starting supplies you can buy are the seeds themselves. While there are plenty of places you can purchase seeds, high-quality seeds will ensure hardy, healthy plants. Starting seeds take a lot of time, care, and patience, and it can be heartbreaking to put in the effort and have your plants die off soon after.

At Stauffers of Kissel Hill, we have a huge selection of common and rare seed varieties for you to plant and grow. We also carry a wide variety of brands, including Burpee, Livingston, and Lake Valley Seeds, so you can plant the healthy, thriving garden of your dreams!

Have More Questions About Seed Starting?

If it’s your first time starting seeds or if you are an experienced grower with questions about a specific variety, our in-store experts are here for you! Stop by or call in for tips and tricks on starting your best harvest season yet!

Ready to start your seeds? Find your nearest Stauffers of Kissel Hill for a high-quality selection of vegetable and flower seeds and all of the seed starting supplies you need!