Zone 10 · Melons Growing Guide

When to Plant Watermelon
in Zone 10

Needs a long hot summer and plenty of space. Compact 'icebox' varieties like Sugar Baby work in smaller gardens. Thump test: hollow sound means ripe. Also check the dried tendril near the stem.

Plant outdoors
Mar 1 – Apr 15
Start indoors
Direct sow
Last Frost
~Jan 15
Days to harvest
75–90 days
Difficulty
Medium
Growing — Zone 10
Harvest window: Jun – Aug

Planting Calendar

In Zone 10, Watermelon should be planted outdoors Mar 1 – Apr 15, after the average last frost date of approximately Jan 15.

Prime zone. Long hot growing season gives excellent yields.

Care Guide

Sunlight
Full sun · 8–10 hrs/day
Watering
Moderate
Spacing
36–60 inches
Soil
Sandy loam, well-draining, warm
Days to maturity
75–90 days
Soil pH
6.0–6.8
plant tip · Zone 10

Prime zone. Long hot growing season gives excellent yields.

Feeding Schedule

How often
every 3 weeks
Feed type
balanced then high potassium
Key timing
switch to high-potassium at flowering

Feed with nitrogen early to build vine, then switch to potassium when flowers appear for better fruit set.

Companion Planting for Watermelon

What you plant next to watermelon makes a real difference — some plants actively help, others compete or attract pests.

Grows well with
  • Radishes
  • Nasturtiums
  • Corn
Keep away from
  • Potatoes
  • Cucumbers
  • Fennel

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Common questions

In Zone 10, direct sow watermelon outdoors Mar 1 – Apr 15 after your last frost date of approximately Jan 15. Prime zone. Long hot growing season gives excellent yields.
Zone 10 has an average last spring frost of approximately Jan 15 and a first fall frost around Dec 31. These dates vary by specific location — use your ZIP code in the plant app for precision based on the nearest NOAA weather station.
Good companion crops for watermelon include Radishes, Nasturtiums, Corn. Avoid planting near Potatoes, Cucumbers, Fennel, which can compete for nutrients or attract pests.
Watermelon typically takes 75–90 days from transplant or direct sow to harvest in Zone 10. Expected harvest window: Jun – Aug.

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Watermelon in other zones
Crop Guides