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Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Planting for a Fall Harvest

This article was published originally on 7/12/2002

If your vegetable garden didn't turn out quite as you had planned this year, have no fear. The time for planting a fall vegetable garden is here. While tomatoes and peppers thrive in the summer heat, many crops prefer the cooler weather of fall. Cool season crops, such as broccoli, cauliflower, and lettuce, may bolt (go to seed) or become bitter in summer making them prime candidates for fall gardening. To get started you'll need seeds and a calendar.

It's All About Timing

Timing is everything in fall gardening. If started too late, vegetables will not have adequate time to produce a crop before being damaged by a hard frost. If started too early, the summer heat can inhibit the growth of cool season crops. Several factors determine correct planting dates. The amount of time needed from planting to harvest is the major consideration. Gardeners should also allow time for the harvest. Tender crops will require additional time. This additional time allows for slower growth in cool weather and ensures a harvest in the event of an early frost. Once you have the total time needed to produce a crop, work backwards from the average first frost to find the sowing date. In Iowa, the first frost arrives between September 30th and October 15th. Below is an example of planting dates based on an October 15th frost date.
Growing Map

Amount of time needed for:

  • Seeds to Harvest Y
  • Harvest Period x
  • Tender Crop o

What to Plant

Vegetables can be classified into three groups based on their cold tolerance. Tender crops will be damaged or destroyed by a light frost, semi-hardy crops can tolerate temperatures in the upper 20sF, and hardy crops will survive temperatures in the low 20sF. When possible, purchase varieties that are short-season or "early" to minimize the time period from planting to harvest. Seed will need to be purchased now before it is removed from stores. Some choices for fall vegetables include:

Tender Semi-Hardy Hardy
Beans Beets Broccoli
Corn Carrots Brussels Sprouts
Cucumbers Lettuce Cabbage
Eggplant Radishes Cauliflower
Okra Spinach Rutabagas
Summer Squash Swiss Chard Turnips

Planting

High soil temperatures can inhibit seed germination. The application of a light mulch will help cool the soil and aid in germination. When planting seeds in summer, the soil surface should be roughed up to aid in seedling breakthrough. Some gardeners may pre-sprout seeds indoors between moist paper towels before planting in the garden, taking care not to damage the tiny plants. Seeds may need to be watered periodically for proper germination.

Frost Protection

The harvest period for tender and semi-hardy plants can be extended by protecting the plants from cold temperatures. Blankets or sheets can be placed over the crop with proper supports to avoid physical damage. Milk jugs or floating row covers can also be used. Remove the protection as soon as the temperature rises above 32F. In a cold frame, certain crops (such as lettuce) can be grown well into the winter months.

Planning for a fall vegetable garden is a great way to make up for spring mishaps or just extend your garden harvest.

For more information see The Fall Vegetable Garden at the Purdue Extension Website or Fall Vegetable Gardening at the Nebraska Extension Website.



This article originally appeared in the July 12, 2002 issue, pp. 96-97.

Year of Publication: 
2002
Issue: 
IC-487(17) -- July 12, 2002