Vegetable Planting Guide - Canada Greenhouse Kits

PALRAM-CANOPIA'S #1 CERTIFIED CANADIAN SUPPLIER SINCE 2007, FREE SHIPPING on $125.00 + orders*

Vegetable Planting Guide

Temperature Comparison Between Cool Season and Warm Season Vegetables

  Cool Season: broccoli, cabbage, and cauliflower Warm Season: tomato, pepper, squash and melons
Germination 40°F to 90°F 80°F optimum 50°F to 100°F 80°F optimum
Growth Daytime 65F° - 80°F preferred 40°F minimum Nighttime greater than 32°F for tender transplants down to mid-20s°F for established plants Daytime 86°F optimum 60°F minimum Week below 55°F will stunt plant, reducing yields. Nighttime above 32°F
Flowering Temperature extremes lead to bolting and buttoning. Nighttime: Below 55°F, non- viable pollen (use blossom set hormones). Daytime: Greater than 95°F by 10 a.m., blossoms abort
Soil Cool Use organic mulch to cool soil. Since seeds germinate best in warm soils, use transplants for spring planting, and direct seeding for mid-summer plantings (fall harvest). Warm Use black plastic mulch to warm soil, increasing yields and

Vegetable Planting Guide

Vegetable Germination Temperature 
minimum 		 Germination Temperature 
optimum 		 Germination Temperature 
maximum 		 Plant Spacing 2 Planting Depth Days to Germination Typical Days to Harvest Age of Transplants (weeks)

Cool Season Crops
Beets 40° 80° 90° 4-6” ¾-1” 10-Jul 60
Broccoli 40° 80° 90° 18” ½” 10-Mar 65T 5-7 a
Cabbage 40° 80° 90° 18” ½” 10-Mar 85T 5-7 a
Carrots 40° 80° 90° 2-3” ¼” 17-Oct 70
Cauliflower 40° 80° 90° 18” ½” 10-Mar 65T 5-7 a
Kohlrabi 40° 80° 90° 7-9” ½” 10-Mar 50
Leeks 40° 80° 90° 4-6” ¼” 12-Jul 120
Lettuce (leaf types) 35° 70° 70° 7-9” ¼” 10-Apr 60
Onion, green 35° 80° 90° 2-3” ¼” 12-Jul 60
Onions, dry (seed) 35° 80° 90° 4-6” ¼” 12-Jul 110
Onions, dry (sets) 4-6” 1-2”
Parsnips 35° 70° 90° 5-6” ½” 15-25 70
Peas 40° 70° 80° 4-6”or 3” x 8” 1” 15-Jun 65
Potatoes 45° 12-15” 4-6” 125
Radish 40° 80° 90° 2-3” ½” 10-Mar 30
Spinach 40° 70° 70° 4-6” ½” 14-Jun 40
Swiss Chard 40° 85° 95° 7-9” 1” 10-Jul 60
Turnips 40° 80° 100° 4-6” ½” 10-Mar 50

Warm Season Crops
Beans 50° 80° 90° 6” or 4” x 12” 1-1½” 14-Jun 60
Cantaloupe 60° 90° 100° 36-48” 1-1½” 12-Mar 85 2-3 b
Corn 50° 80° 100° 12” x 30” or 9” x 36" 1-1½” 10-May 60-90
Cucumbers 60° 90° 100° 6” trellised 24-36” untrellised 1” 10-Jun 55 2-3 b
Eggplant 60° 80° 90° 18-24” ¼” 14-Jul 60T 6-9 c
Pepper 60° 80° 90° 15-18” ¼” 20-Oct 70T 6-8 c
Tomato 50° 80° 100° trellised: 24” between plants ¼” 14-Jun 65T 5-7 c
Squash, Summer 60° 90° 100° 36-48” 1-1½” 12-Mar 50 2-3 d
Squash, Winter 60° 90° 100° 36-48” 1-1½” 10-Jun 100 2-3 d
Watermelons 60° 90° 110° 36-48” 1-1½” 12-Mar 85 2-3 d
  1. Germination temperature – Soil temperature is one of the best methods to determine spring planting time. Plant when soils reach minimum temperature measured at 8 a.m., 4 inches deep. Beans are an exception, being measured at 6 inches deep. Optimum temperatures listed in the table are useful for starting seeds indoors. Maximum temperatures are listed in regards to high soil temperatures that may interfere with seed germination in the summer.
  2. Plant spacing – Spacings given are equal-distance spacing for crops grown in block or close-row style beds. For example, beets, with a spacing of 6 inches are thinned to 6 inches between plants in all directions. In other words, beets are thinned to 6 inches between beets in the row and 6 inches between rows. The closer spacing listed should be used only on improved soils with 4-5% organic matter. Close-row or block style planting works well for raised bed gardening, with blocks/beds 4 feet wide (any length desired) and two-foot wide walkways between blocks/beds.
    1. Cool Season Crops – Cool season crops prefer a cool soil. Lawn clipping and newspapers make an excellent mulch for these crops by cooling the soil, preventing weed germination and conserving water. Apply fresh grass clippings only in thin layers (less than half-inch) and allow it to dry between applications. Thick layers will mat and smell. Do not use clipping from lawns treated with weed killers or other pesticides. Several layers of newspapers covered with grass clippings also work well between rows. Do not use glossy print materials.
    2. Transplanted cole crops – Since cole crops (cabbage, cauliflower, broccoli, and Brussels sprouts) germinate better in warmer soil, they are typically started from transplants in the spring. Days to harvest are from transplants. In the warmer areas of Colorado, these crops produce the best quality when direct seeded mid summer (early July for the Front Range area) for harvest during cooler fall weather. Before planting out, harden off seedlings.
    3. Transplanting vine crops – Vine crop (cucumbers, squash, melons) roots are extremely intolerant of being disturbed, and perform best when grown by direct seeding rather than by transplants. With the use of black plastic to warm the soil, direct seeded crops germinate rapidly. If using transplants, select small, young plants, not more than two to three weeks from seeding.
    4. Tomato family transplants – The tomato family is traditionally planted from transplants. In warmer areas of Colorado, they can also be direct seeded with minimal delay. Days to harvest are from transplants.