In many parts of the country gardeners’ plant hot-set tomato varieties in the spring, that term means that the tomatoes continue to produce fruits as the mercury rises. Then, in the fall, they plant other varieties that tolerate the cooler nights that autumn is famous for. But here in San Marcos I recommend that you continue to plant hot-set tomatoes for fall. Determinate varieties such as Bob Cat, Celebrity, and BHN 444 can produce crops in under 80 days, making them perfect for fall planting. Other fall favorites are Surefire and Sunpride but fun varieties such as Sun Master, Amelia, Solarfire, and Top Gun also do well for us. Fall is also the perfect time to plant cherry type tomatoes which have no problem setting fruit in any temperatures. My favorites are Sweet 100, Juliet and Sun Gold.
Ask your favorite local independent garden center if they have fresh tomato transplants in stock. If not, ask when they will arrive. If they won’t have them, call another nursery. Or do what I like to do. I always take cuttings from my best and healthiest spring plants before I pull them out. They root quickly, and I’ve got plantable transplants within 2 or 3 weeks.
No matter the variety chosen, get out and get those transplants in the ground now! If your spring garden was successful, the same location should work well in the fall. While there is some disease prevention value in crop rotation, it is more important in the fall garden that the plants receive full sun (at least six-to-eight hours) than a new location.
Important to the fall garden are both sunshine and drainage so once your new transplants are in the ground, mulch them to a depth of about two inches. I recommend using native cedar or hardwood mulches because they spread easily and decompose at a moderate rate. The decomposing is slow enough to protect the tomatoes tender roots but fast enough that they can be incorporated into the garden soil after the fall tomato season. Tomatoes are not drought tolerant plants; they need an ample supply of supplemental irrigation. Using mulch and drip irrigation is the most efficient way to do it. So, mulch, mulch, mulch!
When it comes to watering, it should be done when the soil under the mulch dries to one-half inch. One way to check this is just to carefully push your finger into the soil around the plants to check them. Keeping your newly transplanted seedlings properly watered is a must. This is the real trick to establishing healthy transplants during late summer. Keep in mind that transplants from peat pots or cell packs will have restricted root zones which will require at least 2 weeks in the ground for their root systems to enlarge enough to support active plant growth. Until that time, they may need to be watered every day or the plants will become stunted or might even die. Moist but not soggy is the rule - too much water is just as harmful as not enough. Soaking-wet soil will cause root rotting and death in your transplants. So, check the soil moisture before you water. Another way to check is by picking up a bit of the soil around the plant, if it balls together, it still has enough water; if not, apply water. Personally, I plant in trenches or divots as this helps to direct water down to the root zone instead of allowing it to run off and away from the plant, which not only takes away water from the roots but also robs them of the nutrients that get washed away too.
Providing the newly transplanted seedlings a bit of afternoon shade for the first several weeks can really help them to establish a strong root system. I use some frost guard cloth on the west side of the plants, suspended with bamboo stakes to give some temporary shade. It works great and is easy to do and quick to put up and take down. A friend of mine lines cinder block on the west side of his transplants for a few weeks to provide a bit of afternoon shade. He also claims that this provides a good deal of wind protection for his young tomatoes too, which is useful as a warm wind can dry transplants out very quickly.
Each winter, on average, our risk of frost is from December 6th through February 17th. We almost always get frost from December 28th through January 23rd. And we are almost guaranteed that we will not get frost from March 15th through November 14th. So, our frost-free growing season is around 292 days. 292 days! We can get bushel after bushel of veggies from our gardens in 292 days, including lots and lots of delicious tomatoes. But keep in mind that tomatoes do not like a freeze at all. The same tomato vines that are healthy, green, and productive the day before a frost become dying black vines the day after a freeze. If a freeze is forecast, get on out and harvest all you can. Even the green tomatoes.
I hope you are encouraged to get out and plant a fall garden full of tomatoes! After all, nothing in the world is better than a garden in full fruit, and nothing in the world tastes better than a tomato plucked right off the vine.