By Calvin R. Finch
Guest Columnist

April is thought of as the month when the weather has stabilized to the point that no freezes or days below 40 degrees are expected. All the hot weather plants can be placed on the patio and in the landscape.

If you have not planted your tomatoes, do so in the first half of the month. Pepper and eggplant transplants can be put in the second half of the month. Okra can also be seeded. We usually also pull the cole crops and most greens in April. Don’t be quick to pull them, however.

If the weather stays cool, spinach, chard, and other cool weather vegetables can be harvested. Onion tops will not fall over until May, indicating they are ready to harvest. Green beans, summer squash and sweet corn will put on growth in April. Keep them fertilized and irrigated.

To keep the squash vine borer off of the summer squash, apply thiodan dust to the growing point. Sevin does not work. If you can not find thiodan, try Spinosad.

Snapdragons and pansies should perform well in April. Rust will show up in the snaps sometime late in the month or early in May.

Do not expect much for wildflowers this year. We did not receive the rain needed for germination in the autumn or development in the spring. Do not worry too much; some of the seed will still be viable next year. If you do have bluebonnets, coreopsis, poppies or other wildflowers, make sure you allow them to mature and disperse their seed before you mow down or pull the spent plants.

Zinnias and cosmos can be seeded this month. Use cosmos like wildflowers or in the garden. They will reseed all summer. My favorite zinnias are “Dreamland.” They are available as transplants and seem to last the longest time before mildew does them in.

The winter weeds in the lawn are trying to go to seed. Keep them mowed or pulled to reduce seeds available for next winter. It is too late to kill them with herbicides. You may prevent some sand burs and/or crab grass by applying a pre-emergent herbicide like Amaze or XL now. For more detailed information on controlling sand burs, visit the www.plantanswers.com Web site, click to lawn grass and then sand burs.

Sometime this month the lawn grass will begin growing in earnest. After you mow real grass twice, it is time to fertilize. Use a slow release lawn fertilizer like 19-5-9 or an organic fertilizer. April 15 is the earliest you should fertilize and May 15 is not too late.

Modern roses and fruit trees (with fruit) need to be protected by a regular spray program. Organic products that can be used for insects include Spinosad, neem oil and pyrethrins. For fungus, use neem oil and/or sulfur sprays. Manufactured products that work are Sevin and Captan on fruit, and Acephate and Funginex on roses.

The hummingbirds are in the area. Attract them for viewing with blooming plants like pentas and firebush on the patio and put out sugar water feeders. There is a huge choice of feeders. Some are more decorative than functional because they are hard to clean. Mix one part sugar and four parts water by volume. Red food coloring is probably not necessary, but is decorative and does not hurt the birds.

At the end of the month it is probably a good time to quit feeding seed for the summer unless you have goldfinches visiting. They will be showing their breeding colors this month and next just before they leave for their breeding grounds in the north and Canada.

Calvin R. Finch, Ph.D., is a horticulturist and the director of water resources for the San Antonio Water System.