Late Spring Gardening Questions & Answers

Blossom End Rot on young tomatoes.

Telltale leafminer lines on a yellow squash leaf.

Question: How can I get rid of those pesky sticker weeds in the lawn? They hurt my children’s feet.
Slaughter, La.

Answer: The best control measure is to grow a healthy, thick turfgrass that will naturally exclude weeds. To help out you can apply a preemergent herbicide in November. Once this miniature-looking parsley plant has established itself, flowered and set seed, then you’ll need to apply a post-emergent herbicide. An application of a three- or four-way herbicide will kill the weed (lawn burweed) but unfortunately the sticky seed pods will persist and still hurt little feet playing in the yard this year. Look for products that contain 2,4-D and dicamba.

Question: When is it time to plant heat resistant tomatoes for summer production?
Baton Rouge, La.

Answer: Most spring planted tomato varieties will not perform well in our extreme summer temperatures. Plant breeders have developed several varieties that will continue to produce a fair crop through summer. Once night temperatures reach and exceed 70 degrees F, the tomato flower has a hard time pollinating itself. Usually by early May tomatoes planted in the garden should be cherry varieties or varieties like Sun Leaper, Solar Master, Heat Wave, Phoenix, BHN 216 and series, Solar Fire and Florida 91.

Question: My squash, cucumber and tomato leaves all have squiggly lines in them. The leaves look bad! What is causing this and what can I do to prevent it?
Donaldsonville, La.

Answer: Leafminers are tunneling beneath the upper and lower leaf surfaces. Once the larva hatches and enters the leaf there is no control. A very small female fly lays eggs on the leaves and the only opportunity for control is when the egg hatches and the larva begins to burrow into the upper leaf tissue. Total control is impossible but repeated applications of Spinosad, an organic insecticide, will maintain low populations, and can also be used on citrus trees to control the citrus leaf miner on young trees when new growth occurs.

Question: I picked my first tomato and it was delicious but I want to avoid a problem I had last year as the plants went into summer. The bottom on each fruit becomes discolored, soft and rotten. Any suggestions?
Clinton, La.

Answer: You’ve described blossom-end rot. Monitor pH to prevent blossom-end rot. Blossom-end rot appears as a small water-soaked spot near the blossom end of the tomato. The spot eventually enlarges and becomes dry, sunken and brown or black. Insufficient calcium uptake by the plant causes blossom-end rot. Any condition that reduces the plant root's ability to absorb water sets the plant up for blossom-end rot. This can be caused by root-rotting fungus, nematodes, too much water, not enough water, soil compaction or too much fertilization.

To prevent blossom-end rot, maintain a soil pH around 6.5 and supply adequate levels of calcium through applications of dolomitic limestone or gypsum (as recommended by an LSU AgCenter Soil Test Recommendation). Avoid drought stress and extreme moisture fluctuations by using mulch and irrigating deeply once or twice a week.

Avoid over-fertilizing plants with high ammonia-calcium-nitrogen fertilizer. Excessive nitrogen can depress the uptake of calcium. Foliar applications of calcium with products like Blossom End Rot Stop are only short-term fixes. This problem is especially troublesome with container grown plants.
5/5/2011 11:16:02 PM
Rate This Article:

Have a question or comment about the information on this page?

Innovate . Educate . Improve Lives

The LSU AgCenter and the LSU College of Agriculture