Gadenin日本語Get the appThe season is long and it ends on a fixed date
A pumpkin takes roughly 90 to 120 days from sowing, and the last four to six weeks of that are ripening on the vine, which cannot be hurried or finished indoors. That gives the crop a shape unlike most vegetables: everything you do in the first half is really about making sure the second half fits before frost.
Work backwards from your first expected frost. Subtract the ripening time, then the fifty days from pollination, then the weeks to first flowering, and you have the date by which the plant must be in the ground. Almost every failed pumpkin season is a planting date that was two weeks too late.
| Stage | Rough duration | The job | The decision |
|---|---|---|---|
| Sowing to planting out | 3 to 4 weeks | Raise plants somewhere warm | Soil above 60F (16C) before they go out |
| Planting to first flowers | 4 to 6 weeks | Water, mulch, let the vines run | How much room the plant gets |
| Flowering to fruit set | 1 to 2 weeks | Hand pollinate, label dates | How many fruit each vine carries |
| Set to full size | 5 to 7 weeks | Feed, support fruit, keep leaves alive | Whether to stop the vine tips |
| Sizing to cutting | 2 to 3 weeks | Let the rind harden, ease off water | Stem corked and rind hard |
| Cutting to the store | 10 to 14 days | Cure warm and airy | Storage temperature and space |
Sowing and getting the plants out
Pumpkins hate cold soil and hate root disturbance, which pulls in opposite directions. Sow too early and you either plant into cold ground or hold a root-bound plant in a pot. Three to four weeks of raising, in a large enough pot, is the whole answer.
In a climate with a long warm season, sowing directly where the plants are to grow avoids the transplant check entirely and often catches up with pot-raised plants within a fortnight.
- Sow three to four weeks before planting out Two seeds to a large pot, an inch (2.5 cm) deep, somewhere around 75F (24C). Thin to the stronger one at the first true leaf.
- Prepare the ground while they grow Dig a generous amount of compost into each planting station a fortnight ahead. Pumpkins are heavy feeders and the base dressing carries them a long way.
- Plant when soil is above 60F Judge by soil temperature, not the calendar. Below 60F (16C) the roots do not move, and a plant checked now never fully catches up.
- Give the space now, not later Six to eight feet (2 to 2.5 m) between plants for full-sized vining types. It looks absurd for three weeks and correct for the rest of the summer.
The running phase
Once the plant has five or six true leaves it starts to run, and from then until flowering the job is simply to let it build as much leaf as possible. Leaf area now is fruit size later, and there is no shortcut.
This is also when the vines want laying out, when the base of the stem wants checking weekly for borer damage, and when nodes want burying so the plant roots along its length.
- Lay the runners out deliberately Move growing tips into the space you want them to fill while they are still soft. Bend them, never fold them, and do it in the warm part of the day.
- Bury a node every few feet Cover a node with a handful of moist soil every fourth or fifth leaf. Each rooted node feeds the vine beyond it and anchors it against wind.
- Mulch the whole area Straw or black plastic over the run keeps moisture in, keeps weeds down and keeps ripening fruit off wet soil.
- Hold back on nitrogen Too much nitrogen now gives you spectacular leaves and no female flowers. Feed for balance, not for growth.
Flowering, setting and filling
The busy fortnight is the one where females start opening. Every morning during it is a decision: pollinate this one and keep it, or leave it and let the vine put its effort elsewhere. Once you have the number of fruit you want, remove every later female so nothing competes.
Through the filling weeks the plant needs steady water. A large fruit is mostly water and inconsistent watering shows up as a cracked shoulder or a fruit that simply stops growing.
| Job | How often | Why it matters |
|---|---|---|
| Hand pollinate and label | Every morning while females open | Flowers are receptive for a few hours only |
| Remove surplus females | Once the target number has set | Later fruit will not ripen before frost |
| Water deeply | Once or twice a week, a good soak | Shallow watering cracks the shoulders |
| Feed | Every two to three weeks while filling | Low nitrogen, higher potassium |
| Slide a board under each fruit | Once, at fist size | Stops rot where the fruit meets wet soil |
| Check the stem base | Weekly | Vine borer frass is the thing to catch early |
The last month, and the deadline
Around six weeks before your first expected frost, stop the vines. Pinch out every growing tip and remove any flower and any fruit too small to finish. Everything the plant has left then goes into the fruit that can actually ripen.
In the final fortnight ease back on water. Slightly drier conditions harden the rind and raise the sugar in the flesh, whereas heavy watering right up to cutting gives a soft-skinned fruit that will not store.
- Six weeks out, stop the vines Pinch every runner tip and strip off late flowers and undersized fruit. This is the single biggest thing you can do for fruit size and ripeness.
- Two weeks out, cut the water back Reduce watering unless the plant is genuinely wilting. The rind hardens and the flavor concentrates.
- Cut before a hard frost Frost on the leaves is fine. Frost on the rind ends the storage life, so bring everything in ahead of the first hard night.
- Cure straight away Ten to fourteen days at 80 to 85F (27 to 29C), then into a dry room at 50 to 55F (10 to 13C). Do not skip curing to save shelf space.
Record your planting date, first female flower date, pollination dates and cutting dates every year. Three seasons of that gives you a calendar tuned to your own ground, which no general guide can match.