Leaves on tomato plants turning yellow?
Guadalupe County Master Gardeners is responsible for this content, which is not edited by the Wilson County News or wilsoncountynews.com.
Why are the leaves on the bottoms of my tomato plants turning yellow?
1. It could be that the plants are getting too much water. This was a common result with the wonderful rains received in May. Be sure your plants are in an area with good drainage. Mix compost in the soil when planting.
2. On the other hand, it could be that the plants are getting too little water. Using a drip irrigation system is a good way to ensure that your plants get adequate and consistent amounts of water. Be sure to use good mulch, as well.
3. Your soil may be low in nitrogen. Nitrogen gives plants their dark green color. Yellow leaves may indicate a shortage of nitrogen. Additives are available at your local nursery. Be careful not to add too much nitrogen, or you will have beautiful green, bushy plants, and no fruit. You can send a sample of your soil to Texas A&M for analysis to be sure. Check with your local extension service for instructions.
4. It could be that you have lovely bushy plants that are preventing sunlight from reaching the lower branches. If this is the case, there is really no need for concern.
5. If you notice yellow leaves all over the plant, or if the yellowing is spreading, your plants may be victims of a disease. If unsure, you can clip off a piece of the affected plant and take it to your county extension agent for advice.
How much water do my tomato plants need?
The answer depends on the size and type of plant, as well as the soil, and of course, the weather. If you use a drip irrigation system, start by watering 2 to 3 hours every other day and adjust as necessary. You will want the soil to be moist to a depth of 6 to 8 inches. Avoid allowing the top inch of soil to become dry.
I don’t recommend a sprinkler, as it tends to waste water. However, if you choose to use a sprinkler, water early enough in the day so that the foliage dries before nightfall, or diseases may become a problem.
You will find that if you maintain a consistent and appropriate amount of water on your tomato plants, you will have fewer problems with blossom end rot or cracking of the fruit.
I have some beautiful tomatoes this year. How do I go about saving the seeds?
If your tomato plants are an open-pollinated (heirloom) variety, you certainly can save the seeds. If you save the seeds from a hybrid variety, you will not likely get the results you had the prior year.
If you choose to save the seeds, choose a healthy, robust fruit that is in its prime -- not over-ripe. Cut it in half and scoop the seeds and gel into a bowl. Label the variety! Add 1/3 cup of water. Set the bowl in a dark location for 3 to 5 days. A film will develop over the top. Remove the film. Add more water and stir. The good seeds will sink. Pour off the water and repeat until the seeds are clean. Drain the seeds on a paper towel. Then place them in a single layer on a paper plate to dry. Once the seeds are dry, place them in an airtight container and store in a dark place at room temperature.
The seeds will remain viable for years. If you find that the fruits grown from these seeds don’t resemble their parents, it could be that the bees in your garden cross-pollinated the plants with other varieties that were grown nearby, creating a natural hybrid.
Penny Wallace is a Texas Master Gardener with Texas A&M AgriLife Extension. If you have a question to be answered, call the Master Gardeners at 830-379-1972 or leave a message to be answered. The website is guadalupecountymastergardeners.org. The Master Gardener research library is open Mondays from 8:30 to noon, at 210 East Live Oak Street in Seguin.