Gardening here in the Shenandoah Valley is a lot different than in the mountains of Vermont. More than the "extra" month on each end of the growing season, there is the annual bout of heat and drought in mid-summer that makes it difficult to get fall crops established in the Mid-Atlantic. Not only are the "bugs" out in force, but temperatures can be too high for some crops to germinate (lettuce seed goes dormant above 80 F) or in extreme cases, set fruit (tomato pollen fails above 95 F or so).
Right now, for instance, we are in a long period of daytime highs in the high 80's to low 90's and no rain outside spotty thundershowers; and this is typical . So, what to do? Well, I use the same trick that gives us tender young lettuces right through the heat: shade cloth. That, and frequent irrigation -- something we lack in our Princess St Garden -- will get you through just about any heatwave, if you are growing the right varieties.
Timing is especially critical for seed germination under mid-summer conditions. Yessterday was in the mid-80's, but we had an afternoon shower that cooled down the surface soil temps (a soil temp guage, aka meat thermometer is a handy thing to keep around) into the mid 70's and by morning the air temp was 70 F as well. In anticipation of these conditions I took a little time yesterday evening to prep the short bed that had held the early squashes for use as a seedling nursery.
The process is fairly simple. I cleared off the remnants of the squash planting, capped the ooze tube irrigation line (seedling beds are best watered by hand) and added a wheelbarrow load of compost (about and inch) to provide a loose and fertile layer for easy seedling emergence, and then covered the bed with hoops and shade cloth to cool.
This morning I made a series of short furrows across the bed, and planted mesclun, fennel, onions and leeks, radicchio and lettuce. I have some fall broccoli, cauliflower and kohlrabi seed on order, and as soon as it arrives I'll put it in, too (fortunately the brassicas don't suffer from heat dormancy like the greens). After tagging everything and covering over the furrows, I watered heavily...and the cold well water further cools down the surface of the soil.
Immediately after watering I covered the bed back up with the shade cloth. Fortunately it is forecast to be a somewhat murky day, so I think I can count on the soil temp staying below 80 F most, if not all of the day, and the fact is that the lettuce -- our biggest problem in this situation -- really only needs about eight hours to start the germination process, and once that happens the heat won't matter anymore.
We'll check back on this planting around the end of the month and see how things worked out. If all goes according to plan, the seedings should be ready for transplanting to their growing beds by Labor Day...and hopefully the crops that are in those beds now will be ready to come out!
