A common misconception is that fall crops are sown in the fall but if you wait until September to sow that final crop of lettuce or peas, they will have barely emerged from the soil when cooler and shorter days slow their growth to a crawl. The result? Little to no harvest.
Fall crops are harvested in the fall, not sown in the fall – which means that you need to get those crops sown during the summer so that they have time to mature by your expected first frost date. When it comes to fall crops, days-to-harvest is one of the most important bits of detail on the seed packet.
When it comes to growing vegetable to harvest in the fall, the goal is to have a full sized crop, or nearly so, by the first frost date. It’s not as simple as subtracting the days-to-harvest from your first frost date, however. Since weather in the fall gets progressively cooler with fewer daylight hours, crops take longer to mature when compared to a spring planting. So in order to give them sufficient time, you need to add at least 1-2 weeks to the total days on the seed packet.
Working backwards from your first frost date, it’s often surprising how early you have to sow in order to harvest in the fall. Oregon Sugar Pod Snow Peas, for example, take 56 days to mature. Adding 2 weeks results in an expected days-to-harvest of 70 days – working backwards from my first frost date on Oct. 3rd, I would have to sow the peas by July 25.
Many crops are great candidates for a fall crop, namely those that appreciate cooler temperatures and are also relatively quick to mature.
Carrots are one of my go-to fall crops. Why? Because carrots that have grown in the cooler days of fall and have been hit by a bit of frost are much sweeter than those that mature during the summer. In fact, I sow the bulk of my carrots during the summer for fall harvest. When calculating days to maturity for carrots, I still work backwards from my first frost date in early October, even though I don’t plan on harvesting them until several weeks after that. Those last few weeks in the ground don’t contribute very much to growth, but they sweeten them up nicely.
Anyone that has tried growing radishes during the summer knows it’s a fruitless exercise. Radishes prefer it cool and quickly turn woody/overly spicy when it gets too hot. With their need for cooler temperatures and super quick maturity – many of them bulb up in less than 30 days - radishes are the perfect fall crop. Since they are so quick, I usually give them only 1 week of extra time when calculating when to sow.
Some quick maturing varieties of salad turnips (also known as Hakurei turnips) bulb up in as little as 30 days while storage types (purple-top) take about 2 months. Both varieties appreciate the cooler weather of fall and, just like carrots, will get sweeter after a few light frosts.
Another bulb that appreciates cooler weather and matures quickly. Depending on the variety you can be harvesting baby beets (and greens) in as little as 40 days.
One of the most highly anticipated spring crops also makes a great fall crop. I usually stick with snow peas in the fall as they can be picked while still quite young, giving me a larger window of opportunity for harvesting.
Kohlrabi appreciates the cooler weather of fall & doesn’t mind a few frosts. Pay close attention to the days-to-harvest as it can vary from 40 all the way up to 80 days for some of the larger varieties.
Kale is a great fall crop. Not only can it be harvested at all stages of growth, from baby to mature leaves, but it also sweetens up once touched by frost. I harvest it as a “cut and come again crop”, harvesting the larger outer leaves, leaving the small ones in the center to continue to grow. In my short season, I’ll plant once in the late spring and harvest from the same plants all summer long and into the fall. If I wanted some extra kale to beef up my freezer stores, I would sow another round in mid-summer for fall harvest.
Leaf lettuce (as opposed to head lettuce) is another amazing cut-and-come again veg that prefers cooler weather. Unlike kale, however, no matter how much you baby it, it will not withstand the heat of summer and I have to reseed several times for a continuous supply. An early August sowing will give me full sized plants by the end of September which I will pick leaves from until November and even into December in some years. No kidding! What’s the secret to harvesting lettuce in the cooler, sometimes freezing temperatures of late fall? Don’t harvest when the leaves are frozen. Wait until they defrost during the warmer daytime temperatures and you too could be harvesting lettuce well into December.
Unlike climbing beans, bush beans are quicker to mature, giving you an abundant crop in as little as 50 days. There’s no trellis to worry about either. Beans like it warm and don’t do well with frosts so it’s a good idea to give them some extra time. I would give them an extra 3 weeks or even more from the days listed on the packet.
As with most leafy veg, Swiss chard can be harvested at any stage, from baby leaf to fully mature. As an added bonus, my fall chard doesn’t suffer from leaf miners like my summer chard often does.
Although I’ve never had good luck with spinach, I’m throwing that out there as a possibility when it comes to a quick fall crop, especially as, like chard and lettuce, it can be harvested at all stages of growth from baby leaf to fully grown. Spinach can be a fussy, however, and may not germinate well if temperatures are too hot.
Concentrate on easy annual herbs such as dill, basil and cilantro - not only are they quick growers, but they can also be harvested at any stage of growth. Even better, sow some in a pot or window box that can be brought inside if frosty temperatures threaten – this could easily extend your harvest well into late fall/early winter.
Fall crops are a great way of maximizing the use of space in your vegetable garden. Just like so much else in life, however, timing is everything. So get out those seeds now and get sowing - you’ll be glad you did come October as you harvest some garden fresh goodness.