When to plant watermelon in Houston

In Houston, typical last spring frost is January 23 and typical first fall frost is December 29. Typical last spring frost: January 23. Watermelon in Houston is a good fit outdoors. The suitable growing window of 222 days covers the 70–100 days this plant usually needs.

Watermelon

How to grow Watermelon Houston climate Weekly temperatures and windows

Where are you growing?

Comfortable

Comfortable in greenhouse

Comfortable in a cold frame

Watermelon in Houston is a good fit outdoors. The suitable growing window of 222 days covers the 70–100 days this plant usually needs.

When to plantMarch 18 – May 12

Harvest: May 27 – August 20
Season vs crop: 222 grow days vs 70–100 needed
Typical frost (last spring – first fall): January 23 – December 29

Watermelon in Houston is a good fit outdoors. The suitable growing window of 222 days covers the 70–100 days this plant usually needs.

Planting conditions

Direct sow
Grow outdoors
Harvest

Local activity windows for this place and growing method. Blue fill is usually too cold for this plant. Dashed lines are typical last and first frost.

Suitable growing days in a row222

Days to harvest70–100 days from seed

Mar 18 – May 12

Direct sow

May 13 – May 26

Grow outdoors

May 27 – Aug 20

Harvest

Activity	Window	Notes
Direct sow	Mar 18 – May 12	Plant outdoors in this window.
Grow outdoors	May 13 – May 26	Plants grow outdoors until harvest.
Harvest	May 27 – Aug 20	Expected harvest from typical days to harvest.

Direct sow
Grow outdoors
Harvest

Blue fill is usually too cold for this plant. Dashed lines are typical last and first frost (35 seasons (1991–2025)). Adjust a week or two for your conditions.

Planting and growing across the year

Planting is the sow / plant-out window. Growing is daytime air versus this plant’s ideal (21 – 35 °C70 – 95 °F21 – 35 °C (70 – 95 °F)) and tolerable (16 – 38 °C61 – 100 °F16 – 38 °C (61 – 100 °F)) ranges.

Ideal / plantable
Tolerable
Too cold
Too hot
Outside window

Planting uses sow / plant-out rules; growing shows daytime air against this plant’s ideal and tolerable ranges.

Key dates

Typical last spring frostJanuary 23

Low-risk last spring frostMarch 4

Typical first fall frostDecember 29

Low-risk first fall frostDecember 4

Frost-free days339

Outdoor sow dateMarch 18

Direct sow windowMarch 18 – May 12

Suitable growing windowMarch 18 – October 25 (222 days)

Expected harvestMay 27 – August 20

Sow again for a steady harvest

Sow quick crops like radish and lettuce every 1–2 weeks, and slower ones like beans and carrots every 2–3 weeks. Stop when there is not enough time left before your first autumn frost for the crop to mature.

One sowing is enough here; there isn't time for a second.

These dates are deliberately cautious. They come out earlier than common rules like '8 weeks before first frost', because we use the low-risk frost date, leave time for picking and add two weeks for shorter autumn days.

How these dates are judged

Ideal conditions: Daytime air from 21 – 35 °C70 – 95 °F21 – 35 °C (70 – 95 °F).
Suitable conditions: Daytime air from 16 – 38 °C61 – 100 °F16 – 38 °C (61 – 100 °F).
Last frost and first frost: Typical spring and fall frost dates for Houston, shown in the key dates.
Days to harvest: 70–100 days from seed, from typical days to harvest.
Sowing window: Dated sow and harvest bars use frost dates, soil minima, night limits, and last-sow count-back from typical crop timing. Air ratings on the weekly chart colour only weeks inside that same window — see weekly temperatures and windows.

Other plants for Houston

Calculated by Plan & Plant. Method. Data 35 seasons (1991–2025).

Frost and suitability dates are typical figures from climate statistics.

Based on 35 years (1991–2025) of ERA5-Land data from Open-Meteo, for an area of about 10 km. Typical dates, not a guarantee.

Dates for Houston use ERA5-Land cell 29.76, -95.37. How we calculated this · Algorithm 2026-10-season-10.

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