We are now in the depth of summer and believe it or not, it’s time to start thinking about fall vegetable crops. Yes, you read right, time to plant fall veggies!
Our tomatoes, peppers, and cucumbers are collectively known as warm season crops, while leafy greens like arugula, lettuce, kale, and spinach, and root crops like radishes, beets, and carrots are referred to as cool season crops. Cool season vegetables grow well in cooler temperatures but once the days start warming up they stop producing what we like to eat off them and instead start producing seeds. Alternatively, warm season veggies have a hard time growing let alone producing much of anything until the temps start climbing. Most gardeners are familiar with spring cool season planting and if you did any of that this year, well this was the perfect year for spring cool season crops. Now is the time to start thinking about fall cool season planting.
The basic starting point for fall cool season crops is the first frost date, or first severe frost date. Obviously the exact day of when this will happen is impossible to determine, but we can use historical averages to help us out. For our area, the 2nd or 3rd week in October generally brings us our first freeze. So by using October 15th as that date, that’s just over 75 days from today. This gives us enough time to start planning on sowing seeds for your fall harvest.
At this time of year 4-packs of already growing veggies are not available so you’ll have to start from seed. On the back of each seed packet will be a “time to harvest” number which is the time in days from planting the seeds to when the plants will be ready for harvest. There’s quite a bit of variation between plants; radish are in the 28-30 day range, beets and kale are in the middle at 50-65, and rutabaga, Brussels sprouts, and cauliflower are in the 70+ range. Pick your favorites, find the days to harvest number, backtrack from October 15th, and that’s our planting date.
One technique to try that’s especially useful for fall cool weather plantings and the unknown of when the first freeze will occur is multiple plantings. Let’s use arugula as an example, which has a 35 day time to harvest. 35 days prior to October 15th is September 11th. That would be your latest planting date. Then going backwards every 7 days (Sept 4th, Aug 28th, etc.), every 10 days, or whatever you choose, those would be planting dates as well. Planting in stages assures you of a steady crop as there would always be a set of plants ready to harvest while others are still growing. This also assures you of the best chance of getting harvests in before a freeze put a halt to the season.
Cold frames are also very useful for cool season fall plantings but we’re out of space so we’ll discuss this in the future.
Art Smith is a co-owner of East Pierre Landscape and Garden Center, 5400 SD Hwy 34, Pierre