Wildflowers-Hardiness Map

The USDA Plant Hardiness Map

Zone 1	Below -50F	Sow seed in early spring when soil can be worked
Zone 2	-50F to -40F	Sow seed in early spring when soil can be worked
Zone 3	-40F to -30F	Spring: April 15 - June 15	Fall: August 15 - October 1 Dormant plant when soil temp. is below 50F.
Zone 4	-30F to -20F	Spring: April 15 - June 15	Fall: September 1 - October 15 Dormant plant when soil temp. is below 50F.
Zone 5	-20F to -10F	Spring: April 15 - June 15	Fall: September 1 - October 15 Dormant plant when soil temp. is below 50F.
Zone 6	-10F to 0F	Spring: March 15 - May 15	Fall: September 15 - November 1 Dormant plant when soil temp. is below 50F.
Zone 7	0F to 10F	A Fall planting is recommended	Fall: September 15 - November 15
Zone 8	10F to 20F	A Fall planting is recommended	Fall: October 1 - December1
Zone 9	20F to 30F	A Fall planting is recommended	Fall: October 1- December 15
Zone 10	30F to 40F	A Fall planting is recommended	Fall: October 1 - December 15
Zone 11	Above 40F	A Fall planting is recommended	Fall: October 1- December 15

For your convenience, we have reproduced the new USDA Plant Hardiness Map. The hardiness zones are based on the average annual low temperature for each zone. Many factors, such as altitude, snowcover, degree of exposure to wind, proximity to bodies of water, excessive or minimal rainfall, soil types, etc. can create variations within zones. Please understand that these abnormalities can adversely affect your wildflowers. Thus, the spring and fall planting dates should be considered generalizations. The above factors have a dramatic effect on predicting precise sowing dates for each zone.