Gardening Blog

Gardening Blog: Starting Flower and Vegetable Seeds Indoors

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With enough advanced planning, gardening for the year can begin indoors. This includes both flower and vegetable seeds. Keep in mind though that certain vegetables can be planted outside before others. These are classified as cold weather vegetables and include leafy vegetables, cauliflower, broccoli, tomatoes, and others. Plan to begin sprouting these seeds in late February and March. That leaves the warm weather vegetables, which can be started in late March through April. These vegetables include pumpkins, cucumbers, and squash, among many others. For an exhaustive list of cold and warm weather vegetables, contact a local county extension office.


Starting flower and vegetable seeds indoors requires very few supplies. You will need:

- A hand shovel
- Potting soil or peat discs
- Seeds
- Water
- A warm, sunny growing spot
- A growing greenhouse tray with a clear plastic lid
- Scissors

All of these supplies are available at home improvement stores and nurseries, though some of the items may only be available seasonally.

Setting Up Your Growing Container

Greenhouse trays are one of the easiest growing containers to start seeds in. They vary in size from 6 to 72 individual growing cells. When purchased new, the growing kit includes an equal number of compressed, dehydrated peat moss discs that make perfect growth mediums. The greenhouse tray can be reused for years, and dehydrated peat moss discs can be purchased separately. When setting up the greenhouse tray, be sure each growing cell is equipped with its own dehydrated peat moss disc. The discs should be placed in the tray so their divoted side is up. Later on, the seed will be placed in the divot and covered. Then fill the tray with water. The dehydrated peat moss discs will immediately begin absorbing the water and swell to about 2-1/2-inches tall. After about 30 minutes, pour the excess water out of the tray.

Sowing the Seeds

Seeds come in many different shapes and sizes, from very small, like a poppy seed, to quite substantial, like a pumpkin or sunflower seed. Regardless of the size or type of seed being sown, each seed must be sown according to the directions on the seed packet. The back side of the seed packet is full of information. Look for the planting instructions, including planting depth (this may be separated into indoor and outdoor planting depths), sun requirements, planting time, seed spacing, row spacing, etc.

When placing the seed into the peat moss, set the seed to the indoor planting depth specified on the seed packet. Use a sharpened pencil tip to set the seed to the correct depth. Make sure every seed is covered with peat moss before moving on. For most seeds, sow more than one seed (usually two or three) in each peat moss bundle. When the seeds sprout, snip the weaker seedlings with a pair of scissors and keep the strongest plant in each bundle to plant into the ground later in the season.

Care and Maintenance

Seeds need to be exposed to a lot of direct sunlight or they will be weak and have a difficult time surviving outdoors when they are transplanted. A south- or a west-facing window will work perfectly. But if a window is not available, plant growths can be used with a high level of success. Grow light kits can be purchased and used. Also, a simple 2-tube fluorescent light fixture will work well. Simply equip the light fixture with a cool-white tube and a red-light tube to cover the full light spectrum needed by new plants. Fluorescent lights are available in T12, T8 and T5 sizes. T12s and T8s are the least expensive, and fixtures are readily available and easy to find. Be sure to rig the fixture so it can be raised and lowered as the plants grow. Situate the light fixture three to four inches above the plants as the sprout and begin to grow. Young plants need 16 to 18 hours of light every day. Use a timer to turn the light fixture on and off automatically every day to make sure the plants are strong when it is time to transplant them.

Temperature plays an important role in the care and maintenance of seeds started indoors. The room temperature should be kept between 60 and 70 degrees. Do not water the seeds too often. The soil should be kept damp, not soaking wet. Seedlings need enough water for photosynthesis, but not so much water that they actually drown.

The most important need of seedlings is attention. Monitor the progress of the seedlings daily, to be sure the light is in the correct position and amount, to be sure the temperature is correct, to be sure they have enough water, etc. If you sit the grow container in a window sill, rotate the container daily to balance the light exposure. Keep an eye on the weather as the seedlings grow. They will likely be very ready to go into the ground outside when the last threat of frost passes. It is always better to plant later rather than earlier. Over the course of a few days in the spring, take the seedlings outside in the sun for a few hours every day for a week to get them used to the outdoors—a process called hardening off. Be sure to bring them in at night so they do not freeze. If that happens, all of that hard work will be wasted. Once the seedlings are transplanted outdoors, care for them like any other plant start used in the past.