I’d bet many of you are like us: by the time you have good, ripe tomatoes and cool cucumbers for salads, the heat has “done the lettuce in.” Our customers love our lettuce, and we have been able to offer it to them most of the year. But mid-June through mid-September, lettuce hasn’t been “growable” here in Kentucky. Yes, we’ve tried the summer crisps, buttercrunches, and many others billed as “heat tolerant”. There must be heat and HEAT because although they do grow for us, by the time they reach an appropriate size for sale, they don’t have the wonderful sweet taste our customers have come to expect.

This year, that all changed. Actually, we have to give credit to David Redhage of the Kerr Center (http://www.kerrcenter.com) in Poteau, Oklahoma. The Kerr Center invited us to speak on our winter growing at the Oklahoma-Arkansas Horticultural Conference last January. As growers do any time they get a chance, we spent the time between presentations talking about growing. We were talking about the need to be able to grow lettuce in the summer, and the lack of success we have had. David then told us about a lettuce he had grown throughout the summer the past year. He and Simon Billy, also with the Kerr Center, both told us it had stayed sweet and had grown really well. We figured that a lettuce that would take Oklahoma’s heat had a great chance at being a good one for us to try. So we did, and….

It’s wonderful!!! The name of the variety is Jericho. It was developed in Israel for growing in their desert. The only source we knew of last year was Seeds of Change (888-762-7333 or www.seedsofchange.com), but I think more seed companies are carrying it now. It is a large green Romaine, with thick, juicy, crunchy, SWEET leaves. In weeks-on-end of 90 degree heat, it continued to grow. Even at the end of August, the heads we were harvesting were about 10 inches tall, 10 inches across and weighed close to a pound. Our customers are ecstatic that we have a lettuce that they can buy for their summer salads, and our market sales have been terrific. We seed it into 96-cell trays, transplant at four weeks on 1 foot spacing and on installed drip irrigation and harvest in five to six weeks from transplant. To get the best germination in our hot weather, we place the seed trays in the refrigerator (covered), right after seeding, for two to three days to break seed dormancy. We have been planting every two weeks because it holds nicely. And, for those of you who are so inclined, it is open-pollinated, so you may save seed. Our only mistake was in not growing enough because we were “trialing” it – we’ll fix that in 2003!

Shade house mesclun
The other salad success this summer is our mesclun mix. We have tried for years to successfully grow sweet, tasty mesclun during the hot months. This year we finally got it right. We covered one of our coldframes with shade cloth. It grows mesclun that will rival the quality of our fall/winter/spring offerings. One change we made was to take the greens out of the mix. We are using lettuces only. The greens get a little too much insect damage, mostly flea beetle, to make a nice mix. It has been so successful that we intend to erect a frame this winter that will be for shade growing only next summer. Using it, we plan to harvest 540 row feet a week, and figure even that won’t meet the demand.

We seed the mesclun about 17 days before the anticipated harvest date for June through August plantings. Before and after that, it will need about 21 days. We only cut it once, and then turn under the residue. That helps cut down on insects and disease. It sounds like a lot of seeding, but we have done the math: it takes about 3 ounces to seed 300 row feet, and we can cut at least 10 pounds of mesclun (at $8.00 per pound) from that seeding. Seed cost: about $7.60. It will need a lot of water – plan on using the drip at least once a week – maybe twice if it’s really hot. We also had to use BT spray in late summer to control caterpillars, but the harvest is well worth the effort, even with yields lighter than in cool weather.

If you have a coldframe you are using for season extension, consider investing in enough shade cloth to cover it. Mesclun is as big a seller in the hot months as it is in the cool ones, and you’ll probably be the only ones selling it locally!

Alison and Paul Wiediger own Au Naturel Farm in Smiths Grove, Kentucky. They will be holding a one-day workshop on winter growing in hoophouses on Oct. 19. They can be reached at 270-749-4600 or http://aunaturelfarm.homestead.com.