Dept. of Plant and Soil
Science
Indoor Seed
Sowing--
Vegetables
OH90
Dr. Leonard Perry
Extension Professor
Starting seedlings of annual flowers and vegetables indoors has several advantages:
--the fun of watching your own plants grow from seed, getting a jump on spring
--the ability to grow more unusual and different varieties than you often find in retail outlets
--saving money
--using washed and recycled containers from year's prior, helping the environment
--the ability, especially in northern climates, of getting a jump on the season, extending it by several weeks by planting more mature plants than sowing seeds directly
--starting seedlings that are difficulty to sow direct and have survive, especially slow-growing ones
Culture:
--Use a sowing mix for starting seeds, not garden soil. Those that don’t transplant well should be sown in peat pots (indicated in table).
--Sow at a depth of about twice the diameter of the seed; very small seeds can be sprinkled on the surface and allowed to settle in when the container is gently tapped on the sides.
--Keep gently watered, as with a water breaker ("rose") on a watering can. Don't allow to dry out, and don't keep too wet. Be sure to use lukewarm water, especially in the north.
--Sow in individual cells, or in rows in a flat. This way if a disease starts it wont spread too far before you can remove the affected plants and soil. The main disease to watch for is "damping-off", often caused by seedlings staying too wet. Seedlings rot at the base, toppling over quickly.
--Keep in bright light. You may grow under fluorescent lamps for much of the seedling and young plant growth. Use alternating cool and warm white tubes, in a couple of light fixtures side by side over flats. Keep 4 to 6 inches above tops of plants. Hanging fixtures on chains makes it easy to raise them as plants grow. Keep lights on 14 to 16 hours a day, such as on a timer. New thinner energy-efficient tubes are effective and save energy.
--Most seedlings respond to bottom heat, as from seedling heating mats.
--Once seedlings start developing leaves, lightly fertilize them, such as with 1/2 strength liquid fertilizer. Be aware that many organic liquid fish or seaweed fertilizer may have an undesirable odor indoors.
Dates:
- The following weeks are approximate from time of sowing to planting outside, not merely germination times which is what is usually seen in catalogs and on seed packets. Generally those taking more weeks to produce a plant require more days to germinate. So if 6 weeks, and you want to plant outside the end of May, sow mid-April. Weeks may vary slightly depending on variety/cultivar, conditions, and location.
- Two weeks are often given for packs, the first being the minimum to sow indoors and have a plant suitable for planting outside, the second to have a plant almost or in bloom under ideal conditions (high light, warmth, as in a hobby greenhouse or sunroom). If you will grow mainly under lights, or under average home conditions, it may be best to aim for the fewer weeks. Seedlings grown too long indoors with improper balance of heat and light (too warm, too little light) often get spindly.
- Weeks are for sowing in a cell-pack. If sowing in these or flats, to transplant into a 4-inch pot for growing further prior to planting outside, add 2 weeks.
- -Generally these times are for growing seedlings around 65F air temperature, with similar bottom heat. If growing colder add a week, if growing warmer subtract a week. So if 8 weeks is listed, figure 9 weeks if growing at 55-60F, or 7 weeks if growing at 65-70F.
- Generally sowing at the proper depth will give the correct light requirement.
- Many vegetables often just sown outdoors are so marked (o).
- Ease refers to Easy, Moderately easy, or Difficult to grow from seeds.
- Temperature (temp.) is ideal from growing seedlings once germinated, W (warm, 65-75F) or C (cool, 55-65F). If none given, aim for around 65-68F air temperature and similar soil temperature from bottom heat. Plants usually will grow at less than the ideal, just perhaps slower.
- For flowers, see OH leaflet 89. For more perennials and their sowing needs see perrysperennials.info.
|
|
weeks |
|
|||
|
Vegetable, Herb |
pack |
pot |
ease |
Temp. |
comments |
|
Artichoke |
6-8 |
10 |
M |
|
|
|
Basil |
4-6 |
8 |
E |
|
|
|
Beans (o) |
2 |
4 |
E |
W |
sow in peat pots, outdoors when warm |
|
Beets (o) |
5 |
7 |
E |
|
soak seeds overnight before sowing |
|
Borage |
2 |
4 |
E |
|
sow in peat pots |
|
Broccoli |
5 |
7 |
E |
|
|
|
Brussels Sprouts |
5 |
7 |
E |
|
|
|
Cabbage, Kale |
5 |
7 |
E |
C |
|
|
Carrot (o) |
5 |
7 |
E |
|
sow outdoors |
|
Cauliflower |
5 |
7 |
E |
|
|
|
Chives |
5 |
7 |
E |
|
|
|
Corn, Sweet (o) |
2 |
4 |
E |
|
sow outdoors when warm |
|
Cucumber (o) |
3 |
5 |
E |
W |
sow outdoors when warm |
|
Dill (o) |
7 |
9 |
E |
|
|
|
Eggplant |
7 |
9 |
E |
W |
|
|
Gourd, ornamental (o) |
3 |
5 |
E |
|
sow outdoors when warm |
|
Lavender |
10 |
12 |
E |
|
|
|
Lettuce (o) |
4 |
6 |
E |
|
some vars. require light to germinate |
|
Melons (o) |
4 |
6 |
E |
W |
sow in peat pots, outdoors when warm |
|
Onion |
5 |
7 |
E |
C |
often from small plants called “sets” |
|
Oregano |
5 |
7 |
E |
|
|
|
Parsley (o) |
8 |
10 |
E |
|
|
|
Pea, sweet |
2 |
4 |
E |
|
generally not sown indoors |
|
Pepper |
7 |
9 |
E |
|
|
|
Sage |
4 |
6 |
E |
|
|
|
Spinach |
4 |
6 |
E |
|
best sown outdoors |
|
Squash (o) |
2 |
4 |
E |
|
sow in peat pots, outdoors when warm |
|
Summer Savory |
4 |
6 |
E |
|
|
|
Sweet Marjoram |
5 |
7 |
E |
|
|
|
Swiss Chard |
6 |
8 |
E |
|
|
|
Thyme |
5 |
7 |
E |
|
|
|
Tomatoes |
5-7 |
9 |
E |
|
|
3/09
Issued
in furtherance of Cooperative Extension work,
Acts of May 8 and June 30, 1914, in cooperation with the United States
Department of Agriculture.
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