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Tips for Giant Pumpkins

Selecting a planting site

  1. Select a sunny place in your garden. Giant pumpkins thrive best in strong sunshine. The larger the area, the better (300-900 sq. ft.), but smaller areas have been successfully planted too. An area that receives 8-12+ hours of sunlight per day is ideal.

Preparing the soil and mound

  1. The best pumpkins come from the best prepared soil. Dig a hole, 40 to 48” deep, 3 to 5 feet in diameter, and mix the soil well with 6-8 bags (9-12 cubic feet) of soil amendments and/or other high organic content materials: well-aged steer or horse manure, compost, humus. More is better!
  2. Put the mixed soil back in. You should have a mound, 2 to 5 feet in diameter, 16 to 18” high at its center.
  3. Allow 30 to 50 feet between individual mounds if you are planting more than one vine.

Germinating giant pumpkin seeds

  1. Soak seeds overnight in warm water (8-12 hours.) This softens the pumpkin seed’s shell and accelerates germination. Start germinating seeds mid-late April to early-mid May.
  2. Plant seeds in a 4” minimum or larger peat/coir pot, in a seed starting mix, flat, .75”-1.0” deep.
  3. Keep seeds moist and warm, 75-80 degrees F. range, is ideal.
  4. Under these conditions, seeds should sprout in 4-7 days, sometimes even sooner!
  5. After the seedling has developed 1-2 true leaves, it is ready to transplant into the mound.
  6. Or, you may simply sow your seeds directly into the mound. Competitive giant pumpkin growers have successfully used both methods.

Transplanting seedlings

  1. Plant the seedling, peat pot and all, in the center of the mound. Peat pot should be well below the top surface of the mound. Soil surface should be just below the bottom leaves. Transplanting in the late afternoon/early evening will help reduce dehydration, initial sun and wind damage. Water thoroughly.
  2. Protect the seedling from winds, strong sunlight, insects and other potential damage by placing an open cardboard box around the seedling until it gets fully established, usually, 7-10 days.

Watering, fertilizing and general care

  1. Pumpkins are 90% water. Soil should be kept moist. Water daily, to once every 2-5 days, depending on your weather and soil conditions. Watering times should be consistent. Early mornings (5:00 a.m.-8:30 a.m.), late afternoons, and early evenings, in this order, are the best times to water.
  2. Use an organic fertilizer every 5-10 days. Seaweed (kelp) and/or fish hydrolysate are some of the fertilizers currently being used by competitive giant pumpkin growers.
  3. Mulch around the main stem with compost, straw, or well-aged manure, 3”-4” deep. Leave 9”-12” of clearance around the stem. Mulching will help regulate soil temperature, help soil retain moisture and better distribute water and nutrients.
  4. Place a wooden pallet underneath the pumpkin before it gets difficult to move (10-25 pounds) to keep the pumpkin’s bottom from rotting, and to facilitate lifting and transporting it later.
  5. Shade the pumpkin once it reaches 24”-36” in diameter to help keep the pumpkin’s skin from hardening and cracking from the hot, mid-late summer/early fall sunshine.

For more information and ongoing growing tips, please visit:

If you have a giant pumpkin growing emergency, question, or discovery, please email This email address is being protected from spambots. You need JavaScript enabled to view it.

Stuart Shim Copyright 2009, all rights reserved.

Last update: 07/14/2022

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Wegman’s Nursery
492 Woodside Rd., Redwood City, CA 94061
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