I am planning to plant some crops for fall and winter. How should I schedule my sowing?
Dear Perplexed –
Fall is a great time for vegetable growing but many of us feel too burned out by the weeds and heat in July and August when the planning and planting are needed. Fall crops are sweeter in general and weeds are less of a problem. My theory is that the plant sugars are a plant ‘antifreeze.’ It is great that you are extending your season into fall and winter.
The simple answer on scheduling is to determine the days to maturity for each of your crops and count back from when you want them to mature. Most seed catalogs give an estimate of the time needed from sowing (or transplanting) to harvest. Using the Johnny’s Selected Seeds catalog for example, they give this period and also specify if that period is for transplants or direct sowing. Back up a month to six weeks if you are growing your own transplants. Add a week or several weeks depending on how short the days will be when you intend to harvest.
A more complicated answer involves considering crop variety, hardiness, microclimate, and the type of protection that you intend to use. Day length and average daily temperature also enter into fall scheduling.
Another consideration is how much the crop likes cool conditions. Miner’s lettuce, for example, hates summer and I have trouble getting it to grow past early June, but in winter it will freeze solid, thaw out, and double in size the next week. Basil in contrast will turn black when it even hears that frost is in the forecast.
Agronomists divide plants into three categories – hardy, half-hardy, and not hardy- as an indicator of their resistance to frost. Most gardening books contain a list with these headings. The Johnny’s catalog uses a snowflake to indicate varieties that are particularly winter hardy. Even within a particular crop type like arugula, some are more hardy than others. Sylvetta “wild” arugula has been hardy for us in the winter.
Protection takes many forms but I usually think of:
- No protection
- Row cover
- Cold frame and
- Heated greenhouse.
One more consideration is the garden site and protection plans. Our frost date is about October 15 in Asheville (sooner on the peaks – later lower down.) If you watch that first frost you will find your “frost pockets” or cool places on your land. On our farm cool air drains off the north side of Spivey Mountain and sometimes leaves a streak of frost in the lowest areas when our hill slopes are sometimes spared. South-facing land is good for warmth in the fall and in the spring. Structures can reflect sun on their south side and create permafrost on their north side so pick a “microclimate” that will do well in winter.
The main point of row cover and cold frames are to prevent desiccation from cold, dry wind. It also helps the crop warm more slowly as the sun rises on the day after a cold night. Combining row covers inside walk-in cold frames have been particularly effective for us.
So answering your question is complicated. The best information is what worked for you last year on your farm, so keep good notes. In ten years or so you will be able to know with some certainty to when to sow a variety of crops. Here are a few general guides to get you started at about 2000 feet (Asheville).
- Heated greenhouse – sow tomatoes in June for fall harvest and in November for early spring harvest.
- Cold frame – sow winter greens in late August or early September to transplant as soon as the summer crops come out.
- Row cover – direct sow short season crops in September and transplant as late as early October.
- No protection – we stop sowing head lettuce on August 15 but salad mix can go a few weeks later.
Space is limited here but Eliot Coleman’s new book The Winter Harvest Handbook Chelsea Green (2009) is great on this topic. It’s available through local books stores or Growing for Market (www.growingformarket.com.) Remember that he is in Maine so we have more sun earlier than he does.
Stay warm and eat well this winter.
Ask Tom © 2013 Tom Elmore & Organic Growers School
Tom Elmore is co-owner and operator of Thatchmore Farm in Leicester NC. He has grown certified organic fruits and vegetables for 25 years and serves on the Boards of the NC Greenhouse Vegetable Growers Association and the Organic Growers School.