Succession planting

Three methods, named by one extension

West Virginia University Extension describes succession planting as more than “pull one crop and put in another,” though that is one of the methods. The news note “Basics of Succession Planting” and the garden-management page “Succession Planting” line up on three practices. They use different interval wording, so both wordings are quoted here rather than averaged.

The first method is several smaller plantings of the same crop, instead of one planting. The news note says quick crops such as radishes, lettuce, and other salad greens are generally planted at two-week intervals, so the harvest staggers if the weather cooperates. The management page says to stagger plantings of the same variety 7 to 14 days apart, and it names cabbage, lettuce, onions, radishes, and spinach as crops that suit the method. Seven days and fourteen days are both inside a “two-week” description. A page that insists on exactly 14, or exactly 10, has added a precision WVU did not.

The second method is one planting date and several maturity dates. The news note’s example is sweet corn: an early variety it names as “Sweetness” at 68 days, a mid-season variety it names as “Allure” at 75 days, and a late variety it names as “Silver Queen” at 91 days, sown together so the harvest covers several weeks. Those are WVU’s examples and WVU’s day counts. They are not in the Texas A&M tables. The management page says the same idea without those variety names: choose early, mid-, and late-maturing varieties of one crop and plant them at the same time. It lists sweet corn, beans, tomatoes, and cabbage as crops where that works.

The third method is a different crop in the same ground. After spring spinach or radishes, the news note says you can plant tomatoes or peppers. The management page states the rotation as a rule of thumb: when cool-season crops come out, plant warm-season crops; when warm-season crops come out, plant cool-season crops if you want a fall harvest. The exception it writes down is a short crop such as radishes, which can mature in as little as 25 days, so more than one radish crop can fit inside the cool season itself.

Experienced gardeners, the management page says, mix the methods. An early crop is replaced when it is harvested, and a second crop is also staggered, or is planted as both an early and a late variety. The mix is still made of the three methods. It is not a fourth calendar.

Where Texas A&M’s tables limit the stagger

WVU does not publish a Texas frost date, and AgriLife does not publish the sweet-corn variety list above. The way to use them together is to let the cited planting window close the gate, and let the succession interval move only inside the gate.

Austin’s city page uses Austin-Camp Mabry, USW00013958, 1.6 miles from the Census point used for the city. The median last 32°F date there is February 20. Texas A&M’s Table 8 places bush snap beans 1 to 4 weeks after the frost-free date. Applied to that median, the outdoor window is February 27 through March 19. The day math uses the leap-year calendar this site uses for month-day shifts, so it matches the crop page.

WVU’s 7-to-14-day stagger fits inside that window once, and not freely after that. A first sowing on February 27 and a second 14 days later fall on March 12, which is still inside March 19. A further 14 days, to March 26, is outside Table 8’s spring cell. The succession instruction did not repeal the planting-date instruction. Stop at March 19, or take the last sowing on the last day of the window, and do not call the March 26 sowing an AgriLife date. If you would rather follow only WVU and you are not in West Virginia, say that. The Texas crop page will keep showing the Texas window.

The same crop in fall shows why the anchor has to be the first freeze, not a copy of the spring interval. Table 8 places bush beans 8 to 10 weeks before the first freeze date. Camp Mabry’s median first 32°F date is December 3. Ten weeks before that is September 24. Eight weeks before it is October 8. A 14-day stagger that starts on September 24 lands on October 8, on the last day of the window. The next stagger would leave the window. Fall intervals are not spring intervals moved by six months. The frost dates are not symmetric, and the week counts in Table 8 are not the same number on both sides. Bush beans are 1 to 4 weeks after the spring date and 8 to 10 weeks before the fall date. A gardener who “does beans every two weeks all year” has left both cells.

Table 9 of the same AgriLife guide is the days-to-harvest range, which is the raw material of WVU’s second method, without variety names. Bush snap beans are 45 to 60 days. Pole snap beans are 60 to 70. Radishes are 25 to 40, which lines up with WVU’s “as little as 25 days.” Tomatoes are 70 to 90. Spinach is 40 to 60. The table does not say whether the count starts at seeding or at transplanting. That ambiguity is the subject of reading days to maturity. For succession, the useful fact is the width of the range. A 45-day bean and a 60-day bean, if Table 9’s ends really are two varieties and if both are timed from the same event, are 15 days apart, close to WVU’s two-week stagger, without a second sowing. You only get that reading if the packet agrees about the starting event. AgriLife did not name “Sweetness” or “Silver Queen,” and this site will not attach those day counts to a Texas corn page.

Replacing a crop inside the published window

The third method needs two windows, one for the crop coming out and one for the crop going in. Take Camp Mabry again and two Texas cells. Radishes in spring are “6 weeks before / 4 weeks after” the frost-free date, so the window around a February 20 median runs from January 9 through March 19. Tomatoes are 1 to 8 weeks after that median, February 27 through April 16.

A radish sown at the early end, January 9, plus Table 9’s 25 to 40 days, is ready from February 3 through February 18. That is before the tomato window opens on February 27. On paper the radish can be finished first. The ground then sits empty until February 27. The gap is not a reason to drop in a crop neither table mentioned. A radish sown at the late end of its own window, March 19, plus 25 days, is not done until April 13. By then the early edge of the tomato window has passed, and April 13 is still inside the tomato cell, which runs through April 16. Waiting for that late radish leaves only a few days of the tomato window. Succession in that case means an earlier radish, or a tomato set on a date still inside February 27 through April 16, not a tomato planted on whatever day the radish happens to finish if that day is after April 16.

The same discipline applies when the second crop is a pepper, which Table 8 also places 1 to 8 weeks after the frost-free date, or when the first crop is spinach at 1 to 8 weeks before. WVU’s example, spinach or radishes followed by tomatoes or peppers, is the pattern. The dates come from the state table and the station, not from the pattern alone.

Nothing here schedules the sweet-corn varieties from the WVU news note into a Texas city. If you grow those varieties, their 68, 75, and 91 days are WVU’s figures for that illustration. Compare them with the corn window on your own state’s crop page before you treat the three sowings as one legal planting date. Table 8 places sweet corn 1 to 6 weeks after the frost-free date in Texas. At Camp Mabry that is February 27 through April 2. Three varieties sown on one day inside that window are the second method. Three sowing dates that walk past April 2 are the first method leaving the cited window.

Sources

• West Virginia University Extension, “Basics of Succession Planting”: https://extension.wvu.edu/lawn-gardening-pests/news/2019/01/15/basics-of-succession-planting
• West Virginia University Extension, “Succession Planting”: https://extension.wvu.edu/lawn-gardening-pests/gardening/garden-management/succession-planting
• Joseph Masabni, Texas Home Vegetable Gardening Guide, Table 8 and Table 9: https://agrilifeextension.tamu.edu/library/gardening/texas-home-vegetable-gardening-guide/
• NOAA NCEI station USW00013958, Austin-Camp Mabry. Month-day shifts use the leap-year calendar the site uses, so the dates match the crop pages.