I can almost see the head tilt: what? Pumpkins are fall and this is spring! What are you thinking?
Pumpkins are a long warm season crop (85-125 days from sowing to maturity) and should be planted as soon as the risk of frost is past. In McKinney, the last frost date is right around the corner: March 20th. For seeds to germinate, the soil temperature must be over 60 degrees F. (the optimum range is 70-90 degrees F.) and the daytime temperature consistently between 80-85 degrees F.
Our springs are often cool and wet, so to get a jump on the weather, start seeds indoors up to two weeks before the last frost date. Pumpkin roots grow long and thick, so choose quart or gallon size containers. Fill containers with a sterile planting mix to within 1” of the top. Plant two seeds 1-2” deep in each pot. Water the pot with a spray of warm water. Place the pot in a warm place and provide a light source set to be on for 12-18 hours a day. Water the pots daily so that the potting mix is moist but not soggy. Most varieties germinate in 7-10 days. When the seedlings are 2” tall and have their first true leaves, remove the weakest seedling by pinching or snipping it off at the base (don’t pull it out as you may hurt the roots of the remaining seedling). Harden off the seedlings by placing the pots outside in a protected, shady spot during the day and bring pots back inside before the sun goes down. After one week they can be left out overnight as long as the nighttime temperature doesn’t dip below 40 degrees F. Continue to check that the soil is consistently moist. After another week they can be planted in a sunny part of the garden, protected from wind.
When planting into the garden, choose an overcast day or just before the sun goes down. Plant the seedling at the same depth they were growing in the pot. If more than 1” of stem shows above the ground, place soil around the stem to encourage root formation. Protect the seedlings from chilly nights by covering them with a floating row cover, or other product that can be removed during the day.
If you decide to wait until the soil warms, plant seeds on hills and incorporate lots of organic matter into the hill to increase drainage. Space hills 8-10 feet apart (check the seed packet for the recommended spacing according to the variety you have chosen). In the center of each hill make a small depression and sow four evenly spaced seeds. Plant seeds as indicated above.
Pumpkins are heavy feeders. Every three weeks during the growing season, side-dress with compost, fish emulsion, or a 5-10-5 fertilizer. Apply a thick layer of mulch to discourage weeds, conserve soil moisture and keep fruits clean. Don’t allow the soil to dry out.
To encourage a nice, round shape, rotate the fruits occasionally, but turn just a little each time so that the brittle stem is not broken. During the two weeks before the anticipated harvest date, pinch out flowers and small green fruits so that the energy of the plant can be directed to the remaining pumpkins.
Harvest pumpkins when the pumpkins have reached their mature size, the vines and leaves turn brown, the fruit turns from yellow to orange, and the rind hardens (stiff enough that your fingernail won’t pierce the skin). Use shears to cut the stems at least 6” long as possible. All pumpkins must be harvested before the first fall frost (November 12th in McKinney).
Pumpkins need to be cured before they are stored; this process hardens the shell and reduces the water content. Cure pumpkins by laying them in a single layer, without touching, in a warm (70-80 degree F.) place for at least a week. After curing, wipe the shells with a damp cloth dipped in a 1:10 bleach:water solution. A whole pumpkin will keep at room temperature in a cool, dark place for one month and five months in the refrigerator.
Growing pumpkins is easy, fun and rewarding – and won’t it be fun to have a nice collection on the front porch at Harvest time? For an expanded version of this article, including recommended varieties, information on companion planting, and insects/disease to watch out for, go to my blog at www.L3h2inc.com #GrowingthePerfectPumpkin