Organic Vegetable Gardening in An Urban Setting

Vegetable Seed Germination Rates

 All crops have a minimum temperature for germination. Below this temperature, germination will not occur. As soil temperatures approach the optimum for each crop, the rate and percentage of seed germination increases. The chart below shows soil temperature requirements for a variety of vegetables and crops, and how long they take to germinate.

 Here is a list of early starters for the house: lima beans, lettuce, turnips, radishes, beets, carrots, muskmelon, lettuce, cucumbers, onions, tomatoes, eggplants, watermelon, squash, balm, basil, borage, caraway, lavender, clary, fennel, dill, sweet marjoram, rosemary, thyme, and New Zealand spinach.

 Plant tomato seed late in February. These will be ready for the garden with blooms by mid-May. Spring onion sets can be set in deep plats and covered with 1 inch (2.5 cm) of soil mix; provide them with 50-55ºF (10-13ºC) and moderate light.

 

Crop
Minimum Temperature (°C)*
Optimum Temperature (°C)*
Days to Germination
Celery
4
21-23
10-14
Bean, Snap
15
23-29
7
Beet
4
23
7-14
Carrot
4
23-26
12-15
Cole Crops (Cabbage, Cauliflower, Broccoli, etc)
4
18-29
5-10
Cucumber
15
21-29
7-10
Eggplant
15
21-29
10
Lettuce
0
18-21
7-10
Melon
15
26-30
5-10
Onion (bulb)
0
21-23
10-14
Onion (bunch)
0
15-20
10-14
Pea
4
18-21
7-14
Pepper
15
23-29
10
Pumpkin
15
21-23
7-10
Radish
4
18-21
5-7
Spinach
0
21
7-14
Sweet Corn
10
21-29
7-10
Swiss Chard
4
20-23
7-14
Tomato
10
23-26
7-14
Turnip/Rutabaga
15
18-21
7-14

 A:   Remember that the minimum temperature to germinate the seed is also the minimum soil temperature you can plant your seedlings at. The ideal germination temperature is also the ideal soil temperature to plant your seedling.