Harrow, London Planting Calendar & Frost Dates

Harrow Frost Dates & Growing Season

Here's the frost forecast for the next three days (last updated on December 8th, 2025 6:02 AM).

Tonight
Dec 8th
No Frost

Safe

9.6°
7.9°
Tuesday
Dec 9th
No Frost

Safe

10.8°
9.4°
Wednesday
Dec 10th
No Frost

Safe

6.9°
6.1°

Last Frost Date (Spring)

The average last frost date for Harrow is April 15th. We recommend waiting until April 29th before planting tender crops outdoors.

First Frost Date (Autumn)

The average first frost date for Harrow is November 25th.

Growing Season

Based on historical data, the growing season in Harrow is approximately 224 days long.

Harrow Planting Calendar

This weekly planting calendar displays the ideal windows for starting seeds, transplanting, and harvesting.

Legend: I = Start Indoor S = Direct Sow T = Transplant H = Harvest
Generating calendar...

Harrow Monthly Gardening Guide

February

In February, you can start Black Eyed Susan indoors, start Cauliflower indoors, start Oregano indoors, start Pansy indoors, and start Coleus indoors.

March

In March, you can sow Spinach outside, sow Watercress outside, start Luffa indoors, sow Flax outside, and start Cantaloupe indoors.

April

In April, you can sow Butterfly Pea outside, sow Cantaloupe outside, sow Calendula outside, sow Babys Breath outside, and sow Black Bean outside.