In This Section

Topics

When Should I Spend Money to Control Weeds?

Author: Leslie Huffman - Weed Management Specialist (Hort)/OMAFRA
Creation Date: 05 May 2005
Last Reviewed: 05 May 2005


Early in the growing season is the most important time to control weeds. If crops are kept weed free for their Critical Weed-free period - beginning with planting, emergence or budbreak - no yield reduction will occur. Weeds that emerge after the critical period will not cause yield loss, although they may cause other problems.

Critical Weed-free Period for Horticultural Crops
Crop Critical Weed-free Period
Apples, new plantings During May and June
Apples, bearing Budbreak until 30 days after bloom
Beets First 2-4 weeks after emergence
Cabbage, early First 3 weeks after planting
Carrots First 3-6 weeks after emergence
Cucumbers, pickling First 4 weeks after seeding
Lettuce First 3 weeks after planting
Onions First the whole season
Potatoes First 4 weeks after planting
Squash Early plantings compete better
Strawberries, new During May and June
Tomatoes, fresh First 36 days after transplanting

Tomatoes, seeded

First 9 weeks after seedling

Growers may still decide to control late-emerging weeds for efficiency of harvest, improved quality or to reduce the weed seed bank. However, remember that choosing a weed management program that keep weeds controlled during these times will prevent yield loss.

| Top of Page |

For more information:
Toll Free: 1-877-424-1300
Local: (519) 826-4047
E-mail: ag.info.omafra@ontario.ca