Leaf Drop. This summer it has been common for shade trees to drop leaves. Prepare to see even more as trees that put on heavy leaf loads in response to the generous rains received this winter and spring, adjust their foliar load to a level that can be supported in the current dry spell.
We have already received reports of live oaks, Texas red oaks, bur oaks, cedar elms, sycamore, mulberries, hackberries and pecans losing leaves. Adjusting leaf load to match available soil moisture is a survival mechanism practiced by well adapted trees. Some of the leaves that drop will have leaf spots, galls and be discolored, but that is just all part of the process. Sometime before the leaves actually drop, the tree cuts off nutrients and discontinues its defense efforts for the leaves that are being dropped. The pests take advantage.
A special irrigation application won’t hurt the trees dropping leaves but it probably won’t be enough to prevent the leaf drop. Applying fertilizer will not help, so save it for next spring. The affected trees will recover.
Tomato Transplants If you are going to beat the cold weather, the autumn tomato transplants need to be planted as soon as possible. One of the common questions that gardeners are faced with is, “How do we keep the newly planted tomatoes from dying in this heat?” The issue is especially pertinent if you use transplants in two inch peat pots.
Tomatoes can tolerate lots of heat if they are in relatively cool soil and receive adequate moisture. Plant transplants a little deeper than the peat pot or soil ball and water them every day. To keep the soil cool, cover the soil with two inches of mulch. Live oak leaves, compost, shredded brush, and small bark pieces work well.
When you irrigate, the whole root ball must be wetted. Apply the water at the base of the transplant. Drip irrigation will work but I alternate a drip application with an application with a water wand every other day for the first 3 weeks.
Another issue with tomatoes in peat pots is that the peat pot must be thoroughly soaked prior to planting and the edge must not stick-up from the soil when planted. If the peat pot is dry at planting it can be hard to the point that it does not let adequate roots emerge from the pot. If the peat wall emerges from the soil, it can serve as a moisture wick and quickly dry out, again becoming a barrier to root development.
When it is as hot as it is now, be careful if you temporarily plant the tomatoes in small containers (one to two gallons). The wet soil in such situations can heat up enough to cause root rot. Shade the containers or plant in larger light colored containers. Better yet, plant the transplants directly into the garden or in the large container that will be their final home.
Dr. Calvin Finch is Urban Water Program Director for the Texas A&M Institute of Renewable Natural Resources. You can ask Calvin question and hear his answers on the air as he co-hosts the Gardening South Texas on the air at KLUP (AM 930) Saturday and Sunday from 12:00 to 2:00pm.