Primetime Newspapers
By Calvin R. Finch, PhD, SAWS Water Resources Director, and Horticulturist
Week of May 1, 2006 
“May Gardening Guide”  

            May is usually the best time to plant a lawn.  It is warm enough for fast growth, and we expect good rains in May and June.  This year we expect to be in drought restrictions beginning the middle of May so reconsider your options.  Drought restrictions mean we are limited to once/week watering after three weeks are allowed for establishing the grass.  Lawns survive fine under that regime, but it requires a certain amount of discipline.  Consider delaying lawn establishment until the drought is broken.

 

            Fertilize your lawn in early May with organic or slow release lawn fertilizer.  Follow the bag instructions.  Avoid “Weed and Feed” formulas.  Because of timing issues the product is inappropriate for our area and an environmental threat.

 

            In the landscape, plant the heat loving perennials.  Esperanza, poinciana, and lantana are good choices.  Blue plumbago, Turk’s cap and shrimp plant do well in the shade.  For annual color use begonias, coleus, and caladium for the shade.  In the sun, plant zinnias, moss roses, and purslane for hot weather color. 

 

            One of the best groundcovers for sun or shade in the summer can be planted now.  Ornamental sweet potatoes are available in maroon and light green foliage.  One plant can cover a 10 feet circle in one growing season. 

 

            We can plant container grown shrubs and trees all year in San Antonio, but it is harder in hot weather.  Water them in well at planting and mulch over the surface with leaves, bark, pecan shells, or shredded brush.  The mulch conserves water and reduces weed pressure, but it also keeps the soil cool which means the roots operate in a larger reservoir of soil.

 

            May is the month when we begin to harvest tomatoes.  The ones that ripen first are the blossom end-rot affected fruit.  As temperatures go from cool to hot, the stream of calcium provided in the water stream is broken.  The hard black area on the tomato is caused by the calcium deficiency.  Sometimes it is hard to prevent blossom end-rot completely, but sufficient water provided by drip irrigation and a mulched root system reduce the problem.

 

            Watch for spider mites on your tomatoes.  They can be controlled with kelthane if they are treated when they appear.  Even neem oil will provide some control if the pests are treated early in the infestation.  Kill caterpillars with a Bt product such a Bio-Worm Control or Dipel. 

 

            It is not too late to plant okra and Southern peas.  Southern peas provide fresh snap beans or can be shelled.  They also make a great ground cover for the garden if you want something growing through the hottest part of winter. 

 

            Start harvesting potatoes when the blooms appear.  Within three or four weeks, the tops will die and all the potatoes should be dug.  When your onion tops fall over they are also ready to be harvested.  Pull them from the ground and let them cure with the tops still on the surface of the garden.  I store my onions on a picnic table in the shade.  They last until Thanksgiving and if one rots it does not smell up the house.

 

            Hummingbirds are breeding in May.  You will probably only have a pair or two of black-chinned hummers use your sugar water feeders. Reduce the amount of sugar water in the feeder and rinse it every week.  Later in the summer the numbers will increase as the season’s young leave the nest.  I leave my thistle feeders up to accommodate the lesser goldfinches, but you may want to quit feeding the other seeds.  The summer break recognizes the fact that seed plants are more readily available and it reduces the likelihood that rodents will become regulars at the feeders.