HUBBARD COUNTY U OF M EXTENSION: Succession planting for produce all summer long

Even in a small space, you can harvest vegetables all season long with some up-front planning. Succession planting is the practice of seeding crops at intervals of 7 to 21 days in order to maintain a consistent supply of harvestable produce throughout the season.

Succession planting also involves planting a new crop after harvesting the first crop. The second or third crop can be the same as the prior, or different.

Fresh vegetables all summer In a small space, it's best to stick to quick-growing crops like lettuce and radishes, or crops that can grow vertically on a trellis, like peas.

Rather than planting all of the peas and radishes at once, calculate the amount that you're likely to eat in a week.

For example, if you're likely to eat 5 to 7 radishes each week, rather than planting all of the radishes at once, plant about 10 radish seeds one week, 10 the next week, 10 the next, and so-on. Since radishes are harvested after about 3 or 4 weeks, you can use that space for more radishes or another crop once you've harvested them. If you eat fewer radishes later in the summer when other things are available, stop seeding new radishes in June, and instead use that space to plant something else.

Succession planting is most important for determinate crops, which are crops that produce all of their fruit (or edible material) at once.

Indeterminate tomatoes, cucumbers, melons, and peppers will continue to produce fruit off of the same plant, so you don't need to worry about succession planting with these crops.

Similarly, you can typically harvest multiple times from herb plants and they will grow back. Check the seed packet label on your tomatoes to see if the variety you've chosen is determinate or indeterminate.

Succession planting resources and tipsFigure out the average number of frost-free days in your area.

Plantmaps.com is a good resource for this. From there, look at your seed packets to determine the number of days your seeds will require from planting until harvest.

For example: In Ramsey County, the last frost date is May 10 on average, and the first average frost date is October 1. That gives growers 144 days to plant. With that number in mind, check your seed packets to see how long each crop will take from seeding to harvest. That's how you can make plans for each spot in your garden.

How often to re-seedJohnny's Seeds has a helpful table showing how often you should re-seed each vegetable to maintain a continuous harvest if you wish to keep harvesting the same crop each week.

• The radishes you plant in the spring will likely be different varieties than the radishes you plant in mid-summer or fall (this could be said for most crops). Make sure to read seed catalog descriptions when selecting which varieties you plan to use throughout the season.
• Heat tolerance is critical for varieties you'll grow in the summer, especially for cool-season crops like lettuce and brassicas. 
• Some crops can be direct seeded, and others should be started indoors. Extension Educator and Horticulturist Mary Meyer wrote an article for last month's newsletter about seed starting, and the right time to seed various crops.

Sample succession plantingsThe options for succession planting are endless. Have fun experimenting with different succession plans, and make sure to maintain crop rotation in your plans.

• Plant a quick growing crop like radish, and plant your warm season transplants like tomato or pepper after harvest.
• Plant greens in the spring - you may even get a few plantings in before planting your fall crops like broccoli at mid summer.
• Grow a spring variety of a crop like peas, then follow up with the same crop. Things like peas, beans, cabbage and greens can be planted and harvested in both seasons. 
• Grow lettuce in the spring, followed by a relatively short season summer crop like peas, then plant another fall crop of lettuce.

After a late summer harvest of peppers or cucumbers, you can likely still fit in a fall planting of lettuce or kale.

Tarah Young is Hubbard County University of Minnesota Extension educator in agriculture, food and natural resources. If you have any questions about this topic or any others, contact her at 732-3391. If information about agriculture, gardening and natural resources interests you, consider signing up for the Hubbard County UMN Extension Agriculture, Gardening and Natural Resources E-newsletter at z.umn.edu/HCExtensionNewsletter.