Plant Isolation Distances Table

Please note, these distances have been formulated for rural environments – no one has data applicable to urban growing, but the suspicion, and the experience of most SLOLA members, indicate that the distances will vary from these, and sometimes by quite a bit. In the final analysis, one needs to learn one's own growing situation and note air flow and insect activity. These charts also do not account for 'organic' methods which almost invariably means more insects interacting with the plants and create further variances from the figures below.

Plant	Isolation Distance (Ashworth)*	Isolation Distance (USDA)	Pollinator
Amaranth	¼ to 2 miles 1	—	wind, insects
Arugula	½ mile (2640')	660 feet 7	insects
Basil	150 feet	—	insects
Bean, Common	0 to 1 mile 4	0 5, 4	self 2
Bean, Fava	0 to 1 mile 4	0 5, 4	self 2
Bean, Lima	0 to 1 mile 4	0 5, 7, 4	self 2
Bean, Tepary	0 to 1 mile 4	0 5, 7, 4	self 2
Beet	5 miles	—	wind
Broccoli	1 mile	660 feet 7	insects
Broomcorn	—	660 feet 7	self 2
Brussels Sprouts	1 mile	660 feet 7	insects
Cabbage	1 mile	660 feet 7	insects
Cantaloupe	½ mile	¼ mile 7	insects
Carrot	½ mile	—	insects
Cauliflower	1 mile	660 feet 7	insects
Celery	1 mile	—	insects
Chinese Cabbage	1 mile	660 feet 7	insects
Chinese Mustard	1 mile	660 feet 7	insects
Chives	1 mile	¼ mile 7	insects
Collards	1 mile	660 feet 7	insects
Cilantro	½ mile	—	insects
Corn	2 miles	660 feet	wind
Cotton	—	¼ mile 6	self, insects
Cowpea	0 to 1 mile 2	0	self 2
Cucumber	½ mile	¼ mile 7	insects
Dill	1 mile	—	insects
Eggplant	50 feet	—	self 2
Fennel	½ mile	—	insects
Garlic	1 mile	¼ mile 7	insects
Garlic Chives	1 mile	¼ mile 7	insects
Gourds	½ mile	¼ mile 7	insects
Kale	½ mile	660 feet 7	insects
Lamb's Quarters	5 miles	—	wind
Lettuce	25 feet	—	self 2
Melon, Honeydew	½ mile	¼ mile 7	insects
Melon, Musk	½ mile	¼ mile 7	insects
Mustard	½ mile	660 feet	insects
Okra	1 mile	825 feet	self, insects
Onion	1 mile	¼ mile	insects
Parsley	1 mile	—	insects
Pea	50 feet	0 2	self 2
Pepper	500 feet	30 feet	self, insects
Potato	30 feet 3	30 feet 3	self, insects 3
Pumpkin	½ mile	¼ mile 7	insects
Radish	½ mile	660 feet 7	insects
Sorghum	—	660 feet	self 2
Spinach	5 miles	—	wind
Squash	½ mile	¼ mile 7	insects
Sunflower	½ to 3 miles	½ mile	insects
Swiss Chard	5 miles	—	wind
Tomatillo	0 4	30 feet 7	self 2
Tomato	0 4	30 feet	self 2
Turnip	1 mile	660 feet 7	insects
Watermelon	½ mile	¼ mile	insect

Footnotes:

1. Green amaranths may need only ¼ mile, grain amaranths up to 2 miles.
2. See paragraph on Self Pollination in Distance Isolation in the article on Saving Seeds True-to-Type.
3. Potatoes are not commonly reproduced from seed.
4. See note on tomatoes and beans in the article on Saving Seeds True-to-Type.
5. "Distance adequate to prevent mechanical mixture is necessary".
6. Isolation distances for cotton vary from 100' between similar varieties, to ¼ mile between 'upland' and 'Egyptian' types ('foundation' or 'preservation' grade).
7. Extrapolated from similar species.

* Seed To Seed, Ashworth, Suzanne © 2002, Seed Savers Exchange