Home Vegetable Garden Guide

Starting Seeds Indoors

Sowing seeds indoors or in a greenhouse the best method of producing healthy, strong vegetables for your crop and for some vegetable plants, and can also be the only method depending on your climate.

Very small seed is difficult to plant outdoors because of size. Plants that require a long growing season may not have enough time to reach maturity unless started indoors in winter or early spring. And also, by starting seeds indoors or in a greenhouse to transplant into the garden, you can get the variety you want started early and maximize your climates growing season. The timing and arrangement of your transplants into the garden are the most important factors in a successful crop.

From choosing the correct containers to knowing when to transplant the sprouts to the garden soil, there are a few steps and precautions to take while preparing and starting your seeds indoors to get your garden off to a great start.

Plants to Start Indoors

Some plants are better started from seed indoors to establish better root systems. Broccoli, Brussels Sprouts, Cabbage, Cauliflower, Celery, Chard, Cucumber, Eggplant, Lettuce, Onion, Pepper, Summer Squash, Tomato, Watermelon or Winter Squash.

Choosing Starter Containers

Several container choices are available for starting vegetable plants from seed. Commercially sold containers are readily available and include flats, trays, cell packs, or flowers pots in a variety of inorganic or organic materials including peat, plastic, or paper. The most biodegradable containers available on the market today are consequently the easiest to use. They are made of vegetable based materials such as peat, moss or other vegetation that can be planted directly in the garden. Peat and clay containers tend to dry more quickly than plastic containers because they are very porous.

Any recycled containers or household items such as baking trays, paper cups, or egg cartons are also adequate for seed starting provided they are disinfected, have good drainage and are at least 2 inches deep.

Planting Seeds

Choose a light-weight sterile seedling mix to start your seeds. Mix the medium with enough water to moisten the mix well. Fill the container with two to three inches of medium and firm the mix lightly.

Sprinkle 2 to 3 seeds on the surface, press them about 1/4 inch into the mix and cover with a little soil. Water thoroughly and allow to drain completely. If more than one seed germinates, keep the healthiest one and cut the remainder back.

Watering Indoor Seeds

Keep soil moist but not wet. Small, tender seedlings dry out very quickly and can die if not attended to regularly. Remember that roots always must have oxygen, as well as water. Water only when the surface of the soil begins to dry out. Improper watering can be a cause of seedling failure.

Bottom watering helps prevent damage, encourages deep root development and ensures the entire depth of soil receives moisture. Only allow the container to sit in water longer than it takes for all of the soil to become moist.

Lighting Requirements

Seedlings require bright light immediately after germination. One warm-white, 40-watt bulb and one cool-white, 40-watt bulb used together are adequate for seed starting and seedling growth. Fluorescent lights can be used for one year before replacement is recommended. Special grow lights can be used,however, they are more also expensive.

The lights should be no more than 6" above the top of the seedlings. Requirements vary with different plants however, most plants that are started from seed benefit from 12-18 hours of light per day.


Because the growing medium used to start seedlings is usually low in nutrients, a regular fertilization program is important for proper plant growth. Apply a liquid fertilizer high in phosphorous weekly. Dilute fertilizer 1/4 to 1/2 the label's recommended strength and apply sparingly when fertilizing seedlings. Always use a liquid form of fertilizer when fertilizing seedlings.


Keep seedlings in a cool, well ventilated, location. To encourage compact, bushy, vigorous growth while minimizing disease, the temperatures should be 55 - 60° F at night and 65 - 70° F during the day.

Transplanting from Flats

Seeds grown in flats must be transplanted into individual containers before planting outdoors. After the initial set of seed leaves or cotyledons that will wither, a new set of leaves that look like the plants typical leaves will appear. These leaves are called their "true leaves" and you will need to transplant them to their own individual containers when they appear.

Prepare the individual containers with growing medium and make small holes deep enough for the roots. Gently lift and seperate the healthiest looking plants form the seed bed using a narrow tool or utensil. Place the roots into the hole as quickly as possible and press the soil firmly, but gently, around the roots. Water thoroughly and allow to drain properly.

Tip: Sowing into cell packs bypasses the need to transplant the seedlings.

Hardening-Off Seedlings

Most seeds should be sown 4 to 12 weeks prior to transplanting into the garden, but the time it takes for seedlings to be ready for transplanting outdoors will vary. Readiness for outdoor planting will vary with how quickly germination occurs, the growth rate and weather conditions. Quality and quantity of light, temperature and nutrients affect the growth rate. However, seedlings that are held indoors too long perform poorly once transplanted into the garden. Seed catalogs and packets provide information on days to germination and weeks needed to reach transplant size. Plants grown indoors must be gradually introduced to outdoor conditions. If seedlings are not hardened off, leaves may be burned by the intensity of the sun or damaged by wind.

Sowing starter plants

An acclimation period is recommended before placing seedlings directly into the permanent growing site. This first step in hardening off allows plants to adjust to outdoor temperatures. After 7 to 10 days, move seedlings into a shaded area of the garden for 2 to 3 days. This will prevent sunscald.

Transplanting your hardened seedlings or starter plants purchased from a nursery can be sown directly into the garden. Any transplanting will temporarily slow or stop the growth of seedlings. This shock can be minimize by giving is a good drink of water before sowing.