Square Foot Gardeners are natural planners, whether planting or harvesting — or both. This fact is particularly evident when you look at a continuous harvest crop, like lettuce. In a Square Foot Garden, you’re encouraged to plant what you’ll need and also stagger your planting so the crop can be harvested at intervals you can keep up with.
In other words: Not too much. Not too little. You plant just what you need.
What Are Continuous Harvest Crops?
Continuous harvest crops are exactly what they sound like: garden crops that allow you to harvest again and again. Leaf lettuce, for example, is a continuous harvest crop that allows you to a few leaves here and there rather than waiting for the entire plant to reach maturity before harvesting. With lettuce and proper planning, that could mean fresh salad greens throughout most of the growing season.
In addition to leaf lettuce, other continuous harvest crops include radishes, Swiss Chard, parsley, spinach, broccoli, beets, peas, summer squash, and more. (You’ll find a list of continuous harvest crops and planting/harvesting charts in the Square Foot Garden book.)
Square Foot Gardens make it easy to optimize the harvesting schedule of these crops, too, by simply adding some chronological spacing between the planting of each square. So you may already know that you want to plant 3 squares of leaf lettuce but rather than planting all 3 squares at once, you plant the squares 2 weeks apart so to avoid a feast-or-famine scenario.
Continuous Harvest in a Square Foot Garden
Like I said at the start, Square Foot Gardeners are planner. So with lettuce, the goal would be to have fresh lettuce all the time, at least until it gets too hot for optimal taste or growth. This “Planting Schedule for Continuous Harvest Crops” from the All New Square Foot Gardening, 3rd edition book shows how to achieve this.
How to Use the Planting Chart
In the chart, the “0” (zero) on the left represents the average last spring frost date and the “0” on the right is your average first fall frost date. If you don’t know the frost dates for your specific location, you should be able to do a quick online search to find out.
Let’s say you live in Baltimore, Maryland, where the average last frost date in the spring is April 30. Based on the continuous harvest chart, you could start planting lettuce seven weeks before the last frost date and three weeks after. In this example, you’d plant a single square of your Square Foot Garden with lettuce every other week for a total of 10 weeks from around March 26 until May 21. If you’ll need more lettuce, you could plant a square each week instead.
How to Harvest Leaf Lettuce for Continuous Harvest
Leaf lettuces are grown 4/square. As the plants mature, cut just a couple outer leaves off of each plant with a sharp knife for a daily salad and let the center continue to grow for future harvesting. When the square’s plants are done, remove, add a trowel of blended compost to refresh the nutrients in your Mel’s Mix™, and replant (season permitting).
BTW, when your weather becomes too hot for lettuce, you may get an additional week or two by covering with a shade cloth. But do be aware that lettuce can turn bitter when it gets too hot.
Also remember your fall harvest — you want lettuce in the cooler fall months, too, right? Baltimore’s first frost date is October 15. Taking that info to the Continuous Harvest chart, you’ll see that you can plant leaf lettuce 7-11 weeks before the first frost date, which for Baltimore would be July 30 through August 27, for a bountiful fall harvest.
Protecting Square Foot Garden Beds from Late Cold Snaps
It’s easy to protect a Square Foot Garden raised bed from a cold snap with a simple dome. You can make one yourself from a pair of 10-foot lengths of 1/2” PVC pipe, positioned in the bed as shown and held together at the top with a cable tie.
Then put the appropriate cloth over it (e.g., plastic garden sheeting, a large bed sheet, or another covering). Make sure the cloth is large enough to completely cover the bed and overhang it so you can weigh it down with bricks or stones on all four sides.
For More Information
If you love the continuous harvest schedule, check out the All New Square Foot Gardening, 3rd edition book for more. In addition to the Planting Schedule for Continuous Harvest, there are schedules for Spring Indoor Seed-Starting, Outdoor Planting Schedule for Spring and Summer Crops, and Planting Schedule for Fall Crops. The 3rd edition books is currently available Amazon at https://amzn.to/39RbMVE and other booksellers.
Or pre-order the upcoming 2024 edition for shipment in late 2024.
