Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By referring to the USDA zone info for London it's possible to estimate when it's possible to plant fennel.

Planting Calendar for Fennel

Frost tolerance for fennel:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Fennel tend to make it in a bit of cold which tells us that you can plant them quite a bit earlier in the year than other frost tender plants.

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

The last month that you can plant fennel and expect a good harvest is probably September. Any later than that and your fennel may not have a chance to fully mature. If you are starting your fennel indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In London the average date of last frost happens on April 15. You can expect an average low temperature of -5°F in the coldest months of winter.

Keep in mind that USDA zone info for London is an average and the actual date of last frost is different every year. Since half of the time in London there is a last frost after April 15 be ready to protect your fennel if you have a late frost.

USDA Zone Info for London

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in London

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