Starting a Garden From Seeds Indoors

Starting a Garden From Seeds Indoors

— Written By Minda Daughtry and last updated by Rhonda Gaster

Growing your own garden from seed can be a great activity to do for yourself or with your family. If you have never grown plants from seed let this be the year you start. You do not need a greenhouse to grow healthy transplants and many varieties can be started indoors over the next month to transplant to the garden this spring

Raising seedlings indoors will put you a few weeks ahead of the normal growing season. While the soil temperature is still a bit too cold outside for good germination of your seeds, your tender seedlings will grow happily in the warmth of a propagating light shelf. Not only will it give you a head start on the garden season, it can also save money and allow you to grow different varieties of plants that you may not be able to purchase locally.

Light shelves/growing racks can be purchased commercially (they can be pricey)


Light Shelves-Growing Racks

like the one on the left or you can build one yourself very economically and repurpose components as well, such as this one.

The growing rack consists of a heavy duty plastic storage shelving with recycled hanging shop fluorescent light fixtures mounted under the shelf bottoms with chains. You will want to keep the fluorescent lights about six inches above the tops of your seedlings so it is important to be able to raise the light upward as your plants grow.



Fluorescent bulb

While the commercial light shelf came with specialty gro-lux bulbs, Standard fluorescent lighting is all that is needed and not a particular growing lamp light. I used one cool white light bulb and one warm light bulb. The commercial shelving came with built in removeable trays.



Heat mat, bulbs, trays

Consistent bottom heat is key for many types of seeds to germinate. By supplying steady warming to rootzone of your plants, a heat mat encourages successful seedlings and cuttings. Warm season plants to start off early include eggplant, tomatoes, peppers and basil. The family will love them! You just can’t stay mad at anyone when you take a bite out of a fresh homegrown tomato still warm from the Carolina sunshine.



Recycled Food Trays

I have repurposed aluminum foil catering trays to hold my seed starting “flats”. My flats consist of cleaned, previously used divided plant packs, as well as cleaned empty plastic containers that held everything from cherry tomatoes, to eggs, to salad greens. It is vital that your containers have drainage holes. You need the water to get into the soil, function mechanically and chemically as needed and then drain away. Otherwise the root zone will get saturated and soggy resulting in not get enough oxygen to the plant roots and your plants will fail from root rot.

“Soil” mixtures for starting seeds comes in a variety of products. But not all seed-starting mixes and potting soils are created equally. Experienced gardeners generally have their favorites, based on what plant varieties they’re growing and the environment they are working in. Even though it’s not all that difficult to pull together, beginners may be at a loss as to what potting media to select. Extension is here to help with the trusted information you can count on.

The basic difference is soilless seed-starting mixes have a finer texture and are made from ingredients such as milled peat moss, perlite, coconut coir fiber and vermiculite. Potting soils may be used to start seeds, but they tend to be more coarse in texture and may contain, compost or composted manure along with vermiculite, peat moss or perlite. Some seed-starting or potting mixes may contain added fertilizer as well.


Seed Starting Mix

As with all things, READ THE PACKAGE. Some products contain enough fertilizer to provide seedlings with sufficient nutrients to last up to three months, while others may have no added nutrients. If you are making your own mix, avoid incorporating typical garden/field soil. When potting soil ingredients include field soil, compost or manure, they may also contain some weed seeds or other hitchhikers that you don’t want to bring into your seedling’s environment.

There are several key benefits of garden-based learning for children, youth, adults, and families: Nutrition Awareness; Environmental Awareness; Learning Achievements; Life Skills; Health and Wellness; Community Building and Social Connections, and general garden-based learning. Start making memories today with starting seeds indoors. For more information on seed starting resources, contact your local Extension office or email me at minda_daughtry@ncsu.edu.

Minda Daughtry is Horticulture Agent with North Carolina Cooperative Extension in Lee County.

Grow Lights

The natural light from a window is seldom enough for good, strong seedling growth. They will usually stretch and lean towards the light and will not produce sturdy plants. Sowing seeds indoors under fluorescent lights is the easiest way for the home gardener to control growing conditions and grow healthy transplants. Incandescent bulbs give off more heat and less light (mostly red) than fluorescent tubes and will not produce good transplants by themselves.

Many gardeners use inexpensive and widely available “shop lights”-- 4-ft. long lightweight metal fluorescent fixtures that take two T-8 fluorescent tubes (multiply the T-number X 1/8 inches to get tube diameter; in this case 8/8 or 1 inch). T-8 fixtures and tubes have largely replaced and are more energy efficient than T-12 fixtures and tubes. You can hang these fixtures by removing the strip or panel above the tubes and inserting chain or wire through the hole(s) in the top of the fixture.

T-5 fluorescent fixtures and tubes are another option. They are relatively expensive, but typically allow for more rapid and robust plant growth. Unlike T-8 tubes, the T-5 tubes can’t be used in a T-12 fixture (common shop light). Chlorophyll absorbs most of its energy from the violet-blue and orange-red wavelengths. Cool, white tubes (40 watts) produce light in the blue and yellow-green segments of the light spectrum. They are the least expensive and the mostly blue light can produce healthy, stocky salad greens and vegetable transplants. The more expensive full-spectrum fluorescent tubes (“grow lights”) produce a balance of warm (red) and cool (blue) light. “Grow lights” enhance foliar growth and produce thicker stems than cool white tubes and are needed for producing flowers on indoor plants. Some gardeners insert one warm and one cool tube into a fixture to gain the same effect.


.When to Plant Vegetable Seeds Indoors

The proper time to sow seeds for transplants depends on when plants may safely be moved out-of-doors in your area. This period may range from 2-3 weeks (lettuce) to 8 weeks (pepper, eggplant) before transplanting, depending on the speed of germination and rate of growth (see “Germination Information for Selected Vegetable Crops” below). A common mistake is to sow seeds too early and then attempt to hold the seedlings back under poor light or improper temperature ranges. This can result in tall, weak, spindly plants that do not perform well in the garden. Sow tomatoes 6-7 weeks before you expect to plant. You will end up with stocky 8-10 in. tall plants. If they do get too tall, you can lay them down in a trench when planting and turn the growing tip up so only the top 2-3 sets of leaves is above the soil.


What to Plant Indoors

  • Typical vegetable transplants found in garden centers in the spring include cabbage, broccoli, and cauliflower; followed by tomato, pepper, eggplant, squash, cucumber, melon, and lots of different herbs. You can grow all of these under your fluorescent lights PLUS the following: beets, spinach, Swiss chard, kale, mustard, broccoli raab, arugula, Asian greens, onion, leek, bean, and sweet corn!

  • Don’t forget about your need for mid-summer, late summer and early fall transplants to keep your garden productive. It’s difficult to find vegetable transplants in stores beyond mid-June.

  • Use fresh seed or seed that has been stored properly from last year. Surplus seeds should be stored in a cool, dry location, like your freezer.

Tips for quick germination

  • The seeds and growing medium need to be moist and warm to germinate. Generally, 65°-75°F is best for germinating seeds of most plants. This should be the temperature of the growing medium, not the air.

  • Seed germination begins with the absorption of water. An adequate and continuous supply is essential. Once the process has begun, a dry period will cause the death of the embryo. Spray some water from a plastic mister on the growing medium as needed, to keep it moist.

  • Cover the container with a piece of clear plastic or insert the container in a plastic bag. This will increase the humidity and temperature. The plastic should not be in contact with the growing medium. Remove the plastic as soon as sprouts appear.

  • You can buy heating pads to set your containers on to warm the growing medium and speed-up germination. A cheaper and easier approach is to drape clear plastic over your light fixture. The plastic should rest on the frame holding the fixture and not on the fixture itself. Leave the lights on and the heat from the ballast will be trapped inside the plastic tent and keep the temperature at 70º-75º F.

  • The top of your refrigerator is another good warm place for quicker germination.