This week we’ve been busy tilling and raking beds in preparation for some Last Chance sowings.

In our climate zone, with an average first frost date of October 14, the first half of August is the last chance to sow several vegetables and get crops from them before winter. It’s important to know the last date for planting each crop so that you have a reasonable chance of success. For this part we got help from the Virginia Tech Extension Service: Fall Vegetable Gardening. 

The first group of Last Chance sowings are the warm weather crops, such as green beans, cucumbers, zucchini and summer squash.

Here’s the formula (for frost tender crops), for figuring the number of days to count back from the expected first frost date; add the number of days from seeding to harvest, the average length of the harvest period, 14 days to allow for the slowing rate of growth in the fall, and 14 days to allow for an early frost. For example, yellow squash takes maybe 50 days from sowing to harvest, and the plants are good here for 21 days, so the last date for sowing would be 50+21+14+14= 99 days before the first frost. For us that means 99 days before 10/14, so 7/7. But with rowcover to throw over the last planting when it gets cold, the growing doesn’t slow down, and the season is effectively 2 weeks longer, and we can ignore the 14 days for an early frost. So our last planting of squash is 8/5, a whole month later than if we didn’t use rowcover..

But August is way to soon to be thinking about frosty weather, except to ensure we have enough rowcover on hand when the time comes. Here, and in many parts of the country, a frost or two will often be followed by a few more weeks of warm weather, so getting past the first few frosts is the effort. It’s easy to get extra harvests for a month or two from mature plants you already have.

We sow our #6 planting of beans 8/3, 15 days after #5; cukes #5 (slicing), by 8/5 at the latest; and zucchini and summer squash #5 by 8/9.

The second group of Last Chance sowings are cool weather crops that grow here in spring and fall, but don’t thrive in the summer. Beets, carrots, chard, turnips and radishes all fall in this group. It can be hard to get some of these to germinate when the soil is still hot.

On 8/1 we sow beets dry or presoaked for 2-12 hours in a little water – not too much water or for too long, as they need to breather air, or could drown. We sow them 1/2″-1″ deep, tamp the soil, and keep the surface damp with daily watering for the 5 or 6 days they take to emerge. We have tried using shadecloth to help keep the soil moist, but it does cut down the airflow and our climate is humid and fungus-inducing. I like the Formanova/Cylindra/Forono beet. The shape is long (good for slicing), and the flavor is very sweet and the texture tender.

Very early in August, or sometimes in late July, we sow a large planting of fall carrots, enough to store and feed us all winter. Danvers 126 is our workhorse carrot. We use an EarthWay seeder, which is light, easy to use and to empty, and comes at a reasonable price. There are more expensive precision seeders that put the seed out more evenly, and so don’t require the amount of thinning that using the EarthWay does, but we’re happy with our choice. We use pre-emergent flame weeding to remove the first flush of weeds, making it easy to then hoe between the rows.

Carrots and beets are ideal crops for this technique. The goal is to flame the bed the day before the expected emergence of the crop. use a soil thermometer and a table of how many days the crop needs to germinate at various soil temperatures, to figure out which day to flame. For carrots it’s possible to sow a few “indicator beets” at one end of the bed, and as soon as you see the red loops of the beet seedlings breaking the surface, flame the carrots. (But look for carrots too, just in case!) Beets are always a bit quicker than carrots to germinate. Tables of Days to Germination can be found in Knott’s Vegetable Growers’ Handbook (Wiley, 2006), by Donald Maynard and George Hochmuth, and Nancy Bubel’s New Seed Starter’s Handbook. (Rodale, 1988)

We use a handheld flamer attached to a propane cylinder that is in a wheelbarrow pushed by a second person behind the first. this person also acts as a “fire warden”. Some growers mount the propane on a backpack frame. Walking along the aisle between the beds, and wafting the wand diagonally back and forth across the bed takes about 10 minutes for a 100′ (30 m) bed. Flame weeding alone can reduce the hand weeding to one hour/100′. Hand weeding can be reduced to 6 minutes/100′ by flaming after using stale beds which have been hoed 3 or 4 times.

Swiss Chard can also be sowed here in August, for a nice fall harvest. We sow ours in April and just keep it going all summer, fall and (if covered) winter too.

At the beginning of August we sow winter storing radishes, China Rose, Red Meat, Shindin Risoh Daikon and Shunkyo Semi-Long. We also sow Easter Egg small radishes. We can have trouble with flea beetles as well as harlequin bugs on our fall brassica sowings, as the pest numbers have built up over the summer. To avoid these troubles, we put rowcover over the beds until the plants are big enough to stand up for themselves against “pest bullying”.

We sow 6 beds of kale, two each every 6 days, (8/4, 8/10, 8/16, 8/24) until we succeed in getting enough established. Often we’ll get patchy emergence and end up transplanting plants from one bed or one end of a bed to fill out the blank areas.

We sow our turnips 8/15 or up until 9/15 (our absolute latest). Rutabagas need longer than turnips, and we’ve given up growing them because late July weather is just too hot and dry. Brassicas will germinate just fine in hot temperatures – the challenge is keeping the soil moist.