If you planted cole crops such as cabbage, broccoli and cauliflower earlier this spring, they will need a little fertilizer boost. These plants need to mature before summer heat arrives, so they must grow quickly while the weather is cool. A sidedressing of fertilizer about 3 weeks after transplanting helps plants continue to grow rapidly.
Use fertilizers high in nitrogen for sidedressing such as nitrate of soda or blood meal at the rate of 2 pounds per 100 feet of row. You may also use lawn fertilizers that have close to 30 percent nitrogen such as a 30-3-4 or 29-5-4 but the rate should be cut in half to 1 pound per 100 feet of row. Do not use lawn fertilizers that have weed killers or preventers. Fertilizer must be watered in if timely rains don’t do that job for you.
We have a sheet available that gives recommendations on how to sidedress specific vegetable crops. It can be found at: https://tinyurl.com/j2ggaa6 (Ward Upham)