Know Before You Grow: Squash and Pumpkins

From Squash casseroles and stuffed Zucchinis to Pumpkin pies and jack-o'-lanterns, these versatile garden favorites offer something wonderful for everyone! Their history is long and rich, and their potential as a food source as well as a beautiful fall-season decoration is unsurpassed.


Choosing a Variety

Pumpkins and Squash offer a wonderful variety of colors, sizes, and shapes, providing you with many options as far as flavors and applications. You can grow Pumpkins that range from small to giant -- anywhere from about 2 pounds to 100 pounds or more! Some are better for eating while others are mainly used for decoration.

When you're deciding which Squash you want to grow, you can choose from a delicious selection of summer or winter Squash. The summer varieties (which include Zucchini) are best for fresh eating and quick harvests, while the winter ones are great for storing and baking.


When to Start

Pumpkins and Squash are best direct sown outdoors after all danger of frost has passed in the spring and the soil has warmed. They can be sown indoors (at a temperature of 70 to 75 degrees F) 2 to 3 weeks before planting out, but direct sowing is recommended.

If you want Pumpkins for Halloween, plant from late May (in northern climates) to early July (in extremely southern locations). Keep in mind that if your Pumpkins are planted too early they may rot before Halloween.


How to Start

Pumpkins and Winter Squash:

Sow the seeds at a depth of 4 times the size of the seed, siting them in full sun in rich, sandy, well-drained soil. Fertilize before planting and then again every 3 weeks until you harvest. It's very important to keep the plants weeded and well watered. If you're growing your Pumpkins on hills, space the vines about 8 feet apart. If instead you choose to plant them in rows, space the vines 3 to 4 feet apart in rows that are about 8 to 12 feet apart. You can also grow them on a trellis, an option especially appealing if you have limited space. Expect germination in 7 to 10 days.

Summer Squash and Zucchini:

Sow the seeds at a depth of 1 to 1¼ inches, siting them in full sun in rich, sandy, well-drained soil. Fertilize before planting and then again every 3 weeks until you harvest. It's very important to keep the plants weeded and well watered. If you're growing your Squash on hills, space the plants about 4 feet apart. If instead you choose to plant them in rows, space the plants 2 to 3 feet apart in rows that are about 4 to 6 feet apart. Expect germination in 7 to 10 days and harvests in 40 to 50 days.


Special Considerations

Summer Squash can cross with similar varieties such as Acorn Squash and jack-o'-lantern Pumpkins. The cross-pollination will not be apparent with your current crop, but it's not recommended that you use the seeds for the following season. However, summer Squash will not cross-pollinate with Melons or Cucumbers.

If your summer Squash become too large (hard and seedy) they will sap the strength away from the plant that would otherwise be used to grow more fruit. Just throw away any that become too large.

Keep in mind that although squash plants produce both male and female flowers, it's only the Female flowers that produce fruit.

Vining Pumpkins need at least 50 to 100 square feet per hill.


Growing Tips

  • Squash do best in a well-drained, sandy loam that is high in organic matter.
  • Pumpkins and Squash do not transplant easily. If you want to start your seeds indoors use paper containers or some other type of fiber material that will peel away from the roots without causing them any damage. Also, only have one seedling to each container. Peat pots are also good, as they can be planted as-is, thus minimizing root disturbance.
Summer Squash:
  • Summer Squash can be planted any time after there is no longer a danger of frost -- from early spring until midsummer.
  • Summer Squash will produce excellent yields in any well-drained soil.
  • Harvest your summer Squash when they're small and tender. They can over mature rather quickly since they develop so rapidly after pollination, so check your crop frequently in order to pick them at their peak quality.
  • Elongated varieties are best at 2 inches or less in diameter and about 6 to 8 inches long. The smaller "Patty Pan" types are best at 3 to 4 inches in diameter.
  • If your Squash does get too large it can still be used for things such as stuffing or grating into breads and other dishes.
  • Summer Squash develop very quickly and are ready to pick within 4 to 8 days of flowering. This is especially true in hot weather.
  • Take care when harvesting your Squash -- they can bruise and scratch easily, and the leafstalks and stems are prickly, so they can irritate unprotected hands and arms. Wear gloves and harvest with pruning shears or a sharp knife.
  • Storing your summer Squash: place unwashed fruit in plastic bags in your refrigerator's crisper. Use within 2 or 3 days for best quality.
  • The open blossoms (before the fruits appear) are also edible -- they're delicious dipped in batter and fried.

Winter Squash:

  • Harvest the fruits when the rind becomes hard and they're a deep, solid color.
  • You will want to harvest most of your crop before heavy frosts, in September or October.
  • When cutting from the vine, leave about 2 inches of vine attached to the fruit.
  • If the fruit becomes cut or bruised or they are subjected to heavy frosts, use them as quickly as possible or compost them -- keep an eye out for seedlings in your compost pile!
  • Winter Squash should be stored in a dry area that stays between 50 and 55 degrees F. If you need to store them for an extended period of time place them in a single layer, preferably not touching each other. This reduces the chance of spreading rot.

Pumpkins:

 

  • Use a sharp knife or pruning shears to harvest, leaving 3 to 4 inches of stem attached to the fruit.
  • Handle and store as you would other winter Squash.

Pests and Problems to Watch For

Powdery mildew:

  • Plant resistant varieties whenever you can.
  • If you can avoid it, don't apply nitrogen fertilizers late in the season. This will limit the production of succulent tissue, which is the most susceptible to infection.
  • Avoid overhead watering.
  • Remove and destroy infected plants -- DO NOT compost them!
  • Allow for as much air circulation as you can.

Squash bugs:

  • Choose pest-resistant varieties when possible.
  • Early detection is very important, so look over your plants often.
  • If only a few of your plants are infected, you can just collect and destroy the bugs and their egg masses. Boards, shingles, or something similar can be placed on the ground near the plants -- the bugs will often concentrate themselves to that area.
  • You can cover the vines until blossoming begins, at which time they'll have to be uncovered for pollination.
  • Burn or compost plant debris at the end of the season.
  • Chemical insecticides can be used if nothing else works. Follow all label directions and safety precautions.

Cucumber beetles:

  • Choose pest-resistant varieties if possible.
  • Plow early to remove vegetation and discourage egg laying.
  • Sandy soils aren't usually as susceptible to pest problems.
  • Row covers can keep them off until the plants are well established.
  • You can apply a foliar insecticide at the cotyledon stage (the appearance of the first leaves). Be sure to follow label instructions and safety precautions.

Squash borers:

  • After you harvest the fruit, destroy the spent vines to kill any larvae that may be hiding inside the stems.
  • Plow in fall or spring to kill any cocoons that may have over wintered.
  • Some gardeners like to plant a trap crop of very early-planted squash -- it can alleviate pest pressure on other, later varieties.
  • You can remove the borers by hand by slitting the stem with a knife, removing the intruder, and then covering the slit area with soil, which will promote additional root formation. You can also pick the eggs off by hand.
  • Place a barrier or cover over the stems to prevent the borers from laying eggs in the first place.
  • You can catch and destroy the moths -- do this at twilight or in the early morning as they rest on the upper side of the leaf bases.
  • Use an appropriate insecticide, but be sure to read instructions and advise on when to apply, as timing is crucial.
  • Borers are quite susceptible to natural enemies, such as parasitic wasps, especially in the egg stage.

View All Know Before You Grow Topics