Delaware Planting Zones

Stretching just 96 miles from north to south, the First State encompasses three planting zones: 7a, 7b, and 8a. 

This range allows various plants to thrive, from cool-season vegetables in the north to heat-loving perennials in the south. 

Whether tending a backyard garden in Wilmington or managing a farm in Sussex County, understanding Delaware's unique growing conditions is key to horticultural success.

In this article, you will learn: 

Delaware's compact geography belies its diverse gardening potential, from the sandy shores of Rehoboth Beach to the rolling hills of the Brandywine Valley. 

As one of the smallest states in the U.S., Delaware packs a surprising punch when it comes to plant hardiness zones and growing opportunities.

Delaware

Image from USDA

Characteristics of Delaware Planting Region

Delaware's climate is classified as humid subtropical, characterized by hot, humid summers and mild to cool winters. 

The state's proximity to the Atlantic Ocean and Delaware Bay significantly influences its weather patterns, creating microclimates that can vary even within short distances.

As a gardener in the First State, you can expect:

  • Warm to hot summers, with July temperatures averaging around 75°F to 79°F (23.9°C to 26.1°C)
  • Mild winters, particularly in southern areas, with January averages ranging from 32°F to 38°F (0°C to 3.3°C)
  • Coastal influences that moderate temperatures and increase humidity, especially in southern Delaware
  • Occasional extreme weather events, including nor'easters and remnants of tropical systems

Despite these varied conditions, Delaware offers a favorable growing environment for many plants. The state's moderate climate allows for a substantial growing season, with most areas experiencing frost-free days from mid-April through late October.

This provides approximately 170-200 days for cultivation annually, allowing gardeners to explore various planting options.

Challenges of Growing in Delaware

1. Coastal Influences 

Delaware's eastern border along the Atlantic Ocean and Delaware Bay significantly impacts growing conditions. Salt spray can damage plants in coastal areas, while storm surges may lead to temporary flooding and soil salinization.

2. Soil Variability 

Delaware's soils vary dramatically from north to south. The Piedmont region in the north features clay-loam soils, while sandy, well-drained soils characterize the Coastal Plain in the south. Each soil type presents unique challenges for nutrient retention and drainage.

3. Urban Heat Island Effect

The urban heat island effect can artificially extend the growing season and stress plants during peak summer heat in densely populated areas like Wilmington.

The Benefits of Using a Greenhouse in Delaware

While Delaware's climate is generally favorable for gardening, a greenhouse can significantly enhance your growing capabilities:

1. Extend Your Growing Season 

  • Without a Greenhouse: In central Delaware, outdoor planting typically begins in mid-April and ends in late October.
  • With a Greenhouse: Greenhouse gardeners can start seeds early in February and continue harvesting well into December. This extension is particularly beneficial for crops like tomatoes, peppers, and eggplants, which thrive in warmer conditions.

Learn more about your area's specific growing dates and the best vegetables to plant in each part of Delaware.

Customer images of their Greenhouse setup in a similar climate


2. Grow a Wider Variety of Vegetables Without a Greenhouse: 

  • Without a Greenhouse:  

Delaware's outdoor conditions are ideal for heat-loving crops like:

  • Sweet corn
  • Watermelons
  • Cantaloupes
  • Lima beans
  • Snap beans
  • Cucumbers
  • Squash
  • With a Greenhouse: 

You can create microclimates suitable for a wider variety of plants, including:

  • Arugula,
  • Spinach, 
  • Broccoli,
  • Cauliflower, 
  • Brussels sprouts, 
  • Tomatoes, 
  • Peppers,
  • Eggplant, Cucumbers, environment)
  • melons, 
  • Zucchini, 
  • Carrots, 
  • Beets, 
  • Radishes)
  • Kale, 
  • Swiss chard,
  • Collard greens)
  • Basil, 
  • Cilantro
  • Parsley,
  • Rosemary,
  • Thyme, 
  • Green beans, Green onions,
  • Leeks)
  • Lemons,
  • Limes,
  • Kumquats,
  • Figs

Why Planta Greenhouses?

For Delaware, we recommend the following greenhouses:

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