Best wishes for a great Independence Day, 2012!
One way you can get some relief from the record high temperatures we are experiencing these days is to think about the cooler weather coming in a few months. It will soon be time to start seeds for fall planting. This includes not only cool weather vegetables like broccoli, but also biennial and perennial flowers, such as foxglove, hollyhocks and primroses. July is the traditional time to start seeds for fall crops, but with the unusually warm weather and our lengthening growing season, it may be wise to be prepared to start a second round of seeds later in the season. Some vegetables, if started too early in summer, will perish simply from the heat of August. This can be a problem with lettuce, for example.
If you only plan on starting a few plants, you can protect them from the worst heat by moving them into the shade for part of the day. Don’t starve them for light, though, or they will not bear a good crop. This advice applies particularly to broccoli and cauliflower, but also to sun-loving flowers like foxglove.
I prefer to start seeds in small pots rather than cell trays. I visit our local greenhouse supply company to purchase square three-inch pots and carrier flats that hold 20 pots each. I use green plastic pots that are intended for nursery production of houseplants and blooming stock. These slightly heavier plastic pots cost a little more, but will last many seasons. Thinner, black plastic pots and carriers typically can be used about three times before sun and handling take their toll. Fortunately, they are recyclable.
Pots hold more soil than seedling cells and therefore remain moist longer and provide more room for growth if the weather, for example, forces me to hold off on transplanting for a week. Brassicas do not take well to adverse conditions during their early development. Stunted plants typically do not yield well. Given the other hazards associated with trying to grow these cool season crops during a sweltering Southern summer, it is wise to take every precaution.
I mix pelletized, time-release fertilizer into the planting mix before I fill pots. Since I know how many pots I will be seeding, I add the appropriate amount of fertilizer based on the instructions on the bag. I prefer a 14-14-14, 30-day formula for all vegetable and flower starts. An equivalent organic fertilizer mix can be substituted, if you prefer.
This season we will be growing the following varieties for fall and winter production:
· Broccoli ‘Thompson’
· Cabbage ‘Savoy Perfection’
· Chard ‘Bright Lights’
· Chervil ‘Brussels Winter’
· Corn Salad ‘Vit’
· Kale ‘Lacinato’
· Leek ‘King Sieg’
· Lettuce ‘Ashley’
· Lettuce ‘Lollo Rossa’
· Lettuce ‘Rouge d’Hiver’
Depending upon maturity times, we will begin starting seeds around July 15-20, or 90 days prior to the first frost date. We use October 20 as the likely first frost date, based on NWS data and our experience. Brassicas and Swiss chard remain in the pots about 30 days prior to transplanting, while chervil, corn salad and lettuce need only two to three weeks. Leeks, on the other hand, need about 6-8 weeks to get big enough to transplant.
We also handle leeks differently from the other transplanted crops. We plant them thickly in one large pot, as they seem to benefit from a little crowding. This method also takes up very little room on the greenhouse bench. A 10-inch pot will hold enough seedlings for about 30 feet of transplants.
Keep all seedlings well-watered. On hot days, this may mean twice daily or more often. Move plants to a shady spot, as mentioned previously, if they show signs of wilting despite irrigation.