Q: Where can I buy bulk corn gluten meal? I want to do an organic care program on my 5000 square foot lawn.
A: Local nurseries sometimes carry small bags of the meal but you can also order it online. Expect to pay around $1.50 per pound for it, whether bought locally or online in bulk, due to shipping costs.
Using corn gluten meal for lawn weed control, you’ll need 20 lb. per 1000 sq. feet. The meal controls weeds by inhibiting root formation. It will control winter weeds if applied in September and summer weeds if applied in mid-March.
The meal is also a good organic fertilizer (10-0-0), so it helps turfgrass grow vigorously to suppress weeds. Remember that corn gluten meal has no effect on perennial weeds like violets, wild onion or dandelion.
Tim Murphy, my weed control guru, says corn gluten meal, a by-product of the corn milling process, was discovered to have pre-emergence activity on crabgrass and a few other annual weeds. Research in Iowa showed fifty percent control of crabgrass.
However, corn gluten meal has not performed as well in research conducted in several southern states. In both Arkansas and northern Florida, ten weeks after application control was less than fifty percent or in some cases non-existent.
Most synthetic pre-emergence herbicides provide eighty to one hundred percent crabgrass control twenty weeks after application.