Summer Squash Guide

Planting Summer Squash and General Gardening Information for Piedmont NC

What you will need to create a Community Garden:

• Area– Pick a spot outside with at minimum of 6 to 8 hours or more of direct sunlight. It’s better to have morning sunlight and shade in the afternoon sun. This prevents damage to the plant from the sun.

• Soil– You need a well-drained soil (potting soil/mix) with a compost of some sort.

Important Growing Information

• Planting Months-
  • Sow seeds inside late March through early April. Check your seed package for exact time for that specific variety.
  • Transplant outside May through August.

• Sowing Seeds and Transplanting–
  • Sow seed indoors, there are many ways to do this but I will give you a brief description:
    • You need a seed starting soil, seed tray with lid, and heating pad/or grow light.
    • Put soil in trays then bury 2 to 3 seeds per hole an inch deep.
    • Water soil until moist but not soaking.         
    • Set tray on heating pad or under grow light.
    • Soil temperature should be 75 to 90 degrees.
    • Place lid on top of tray and make sure there are vent holes in the lid for air circulation.
    • Continue to keep soil moist throughout the germination process.
    • Once the seed germinates (emerges from soil) they will need sunlight or a grow light. They will need 6 to 8 hours of daily light.
    • Before you put the plants outside make sure the average daily temperature is above 55°F consistently (after the last frost of the season) and they must be hardened.

• Hardening Process-
• Gradual Exposure:
• Day 1-2: Place the seedlings outdoors for a couple of hours in a shady, protected spot.
• Day 3-5: Gradually increase the amount of sunlight the plants receive each day, working up to 6 hours of direct sunlight.
• Days 8-10 (or until transplanting): Continue to increase sun exposure until the plants can tolerate full sun for the entire day.
• Watering: 
• Reduce the frequency of watering during hardening off, but don’t let the plants wilt. This encourages deeper root growth.
• Monitoring:
• Regularly check your seedlings for signs of stress like wilting, leaf discoloration, or sunburn. Bring them indoors or protect them with row covers if temperatures drop below their minimum tolerance levels or if strong winds are forecast.
• Transplanting:
• Once your seedlings are hardened off (typically 7-14 days), transplant them into your garden or container. Choose a cloudy day if possible to reduce heat stress. Water the plants well after transplanting. 

• Transplanting outside–
  • Dig a hole and mix fertilizer in the bottom of the hole. Do it on a cloudy day or evening (avoid direct sunlight). Then water well.

• Watering–
  • Water 2 to 3 times a week.
  • They like moist soil.
  • Always check soil with the full length of your finger before watering.
  • On 90°F plus days check soil, it can dry out quickly.
  • Water in the morning around 7am or before. This is preferred but you can water in the evening when sunlight is not directly on the plants.

• Fertilizing–
  • Get a good all-purpose fertilizer or any you prefer. Read instruction for how much and apply every 2-3 weeks. Make sure you water it.

• Pruning–
  • You want to start at the bottom of the plant, prune stems and leaves close to the main stem.
  • Your stopping point for pruning leaves is the flowers. Do not prune above flowers or next to flowers.
  • Prune yellow or diseased leaves.
  • Always prune below the flowers or fruit.
  • Leaves that are touching the soil or very close to the soil are more susceptible to disease, you may want to prune those.
  • You may also want to sanitize your pruning tools with soap and water to prevent the spread of diseases from plant to plant. (Example-if you know there is powdery mildew on the leaf of one plant and not the other. Prune the non-diseased first then diseased one, after finished sanitize your tools.)

• Harvesting–
  • Check the package for when to harvest based on the type of squash planted. Use garden shears, cut the stem, leaving about a ½ to 1-inch portion. Do not twist the squash off. It can damage the plant.

Varieties of squash that grow well in NC:

• Good Varieties of Squash –
  • Yellow straight neck: Grand Prize, Enterprise, Lioness F1, Multipik
  • Yellow crookneck: Dixie
  • Zucchini: Senator, Spineless Beauty
  • Patty pan: Sun Burst, Peter Pan

• Note: But you can choose any variety you would like, just make sure that this is a variety that would grow well in North Carolina (growing zones)

Common Problems and Possible Solutions:

• Diseases–
  • Powdery Mildew: 
    • This is a very common fungal disease that appears as white powdery spots on the leaves and stems of squash plants. It thrives in humid weather and can lead to plants yellowing and dying.
  • Downy Mildew: 
    • Another fungal disease favored by high humidity. It presents as yellowing or brown spots on the leaves, especially on the undersides.
  • Viruses: 
    • Several viruses can infect squash plants, such as Cucumber Mosaic Virus (CMV), Zucchini Yellow Mosaic Virus (ZYMV), and Watermelon Mosaic Virus (WMV). Symptoms include distorted leaves with mosaic patterns and mottled or malformed fruits.
  • Blossom-End Rot: 
    • This is a physiological disorder, not a disease caused by a pathogen. It results in a dark, sunken spot at the blossom end of the fruit. It is caused by a calcium deficiency in the developing fruit, which can be due to a lack of calcium in the soil or the plant’s inability to absorb it.
  • Bacterial Wilt:
    • This disease is transmitted by cucumber beetles. Symptoms include wilting leaves that eventually turn yellow and die.

• Treatments for Diseases–
  • There are a lot of different ways to fix and prevent some of these diseases, it is based on what you would prefer.  
    • For fungal diseases you can use neem oil or a copper fungicide.
    • For viruses you should try to get rid of that plant before possible spread to other plants.
• Bugs–
  • Squash Bugs: 
    • These bugs are small, grayish brown, with a flat back and orange to orange-brown stripes on the edges of the abdomen and underside.
    • They use a straw-like mouth to pierce the surface of the plant and suck out sap, which can cause wilting and plant death.
  • Squash Vine Borers: 
    • These are the larvae of a clear-winged moth. They tunnel into the stems of squash plants, feeding on the plant from the inside and disrupting the flow of water and nutrients. This often causes wilting and can ultimately result in plant death.
  • Cucumber Beetles: 
    • Both striped and spotted cucumber beetles can affect squash plants. Adults feed on foliage and flowers, and in high numbers, they may also feed on stems and fruit.
    • More significantly, these beetles can transmit the bacteria that causes bacterial wilt, a disease that can cause plants to wilt and die prematurely.
  • Aphids: 
    • These are small insects that feed on plant sap, and in large numbers can cause stunted growth and misshapen leaves. They can also transmit viruses.
  • Spider mites: 
    • These tiny, eight-legged mites that feed on the underside of leaves, causing yellowing and discoloration.
    • Severe infestations can stunt or kill plants and may be accompanied by fine webbing on the underside of leaves.  

• Treatments for Bugs –
  • Insecticides
    • Make sure you get the sprays that are for elidable plants. Also, READ THE DIRECTIONS on the spray carefully.
  • Natural treatments
    • Neem oil, Insecticidal soap, Vinegar spray, Diatomaceous Earth.