Growers may be wondering whether to replant pumpkin fields where the stand is uneven due to excess moisture. Potential yield of the replants is one thing it would be good to know.
We have data on yield of pumpkins direct-seeded or transplanted in mid-July in northern Indiana. The trials were no-till planted into a harvested wheat field. Pumpkins were harvested in mid to late October. Yield of direct-seeded pumpkins ranged from 0 to 0.6 tons per acre for 8 varieties in 2004, and from 2.6 to 6.4 tons per acre for 5 varieties in 2005. Yield of transplanted pumpkins ranged from 2 to 8 tons per acre for 8 varieties in 2004 and from 4.4 to 9 tons per acre for 5 varieties in 2005. For comparison, typical yields at this site for an early- to mid-June planting date with conventional tillage range from 10 to 25 tons per acre.
Weather explains some of the difference in yield between years. During the pumpkin crop period in these trials (July 15 to Oct. 20), average temperature at the trial location was 68°F in 2005 and only 62°F in 2004. Growing degree day (GDD) accumulation for the period was 1807 in 2005 and only 1424 in 2004. For comparison, the 30-year Normals for July 15 to Oct. 20 are 64°F and 1535 GDD for the trial site, 67°F and 1736 GDD for Indianapolis (SE side), and 70°F and 1975 GDD for SWPAC in Knox County.
Based on this information, seeding pumpkins now in northern Indiana probably won’t produce an acceptable yield at a reasonable time. Mid-October is late to be starting a pumpkin harvest for most markets. In southern Indiana the yield would probably be greater and the harvest earlier. Early-maturing pumpkin varieties would be the best bet. Since there isn’t as much time for vines to grow, a restricted vine or bush variety that branches earlier in its development and produces pumpkins on the branches should have a better chance of setting multiple fruits early enough for them to mature than a variety that produces one main vine with pumpkins spaced along that vine. If normal practice is to use wide row spacings (e.g. 10 ft. or more) to accommodate vigorous vine growth, it may be possible to reduce row-spacing if a variety with smaller vines is used. Compared to full-size pumpkins, seedings of mini-pumpkins, small pie pumpkins, and gourds are more likely to produce an earlier yield.
If reseeding seems like the way to go, note that any pumpkin plants from the original seeding will very likely produce more fruit per plant than the replants. If original plants are present in any significant number, it’s probably worth thinking about a way to save them when replanting. Don’t forget to review herbicide labels for any replant restrictions.
Yield is important, but is just one of several considerations that go into a decision about replanting. If there is more information you need to help with a decision, please feel free to contact me.