One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By reviewing the USDA zone info for London it's a good idea to figure out when it's possible to plant zinnia.

Planting Calendar for Zinnia

Frost tolerance for zinnia:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since zinnia require warm weather it's important to wait until after the last frost has passed before you can plant them.

The earliest that you can plant zinnia in London is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant zinnia and expect a good harvest is probably August. If you wait any later than that and your zinnia may not have a chance to really do well. If you are starting your zinnia indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in London. It might get as low as -10°F during the coldest months of winter.

Always keep in mind that USDA zone info for London is not always accurate and the actual date of last frost changes from year to year. Half of the time in London it frosts late in the year after April 15 so be sure to be ready to protect your zinnia if you have a late frost.

USDA Zone Info for London

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in London

You may be interested in your other planting guides for London.