Isolating Heirloom Varieties


At first this may seem a little confusing even overwhelming, but if you want grow heirlooms and keep the highest purity for seed saving then you need to know a little bit about isolating various plants. So in this post I’m gonna give you some good information regarding isolating your heirloom varieties for the highest purity and how to avoid those hybrids.

The most important part of isolating heirlooms is to know what plants to isolate from each other. Some vegetable varieties are part of the same species and even though it is a different plant entirely you will still want to isolate them from each other for instance, summer squash and winter squash or cantaloupes and pumpkins. These belong to the same species, and are also cross pollinators, so they need to be separated at least 600 ft apart.

Other plant species you will want to separate from each other is the brasiccas such as broccoli, kale, cauliflower, cabbage, radish, mustards, collards, and chinese cabbage, and because these are also cross pollinators you will need to separate at least 600 ft.

With self pollinators you still will want to isolate them from other similar varieties because their is a chance for cross pollination to occur, however you will not have to space them quite as far apart as cross pollinators. For instance you will want to separate you Red Brandywine Tomatoes from Your Cherokee Purple tomatoes by at least 30 ft.

And contrary to what some say cucumbers will not cross pollinate with squash; they can only cross pollinate with plants of the same species. However Ashley cucumbers will cross with Straight 8’s for instance. Trying to cross cucumbers with squash is like trying to cross Mocking birds with Blue jays. Here is a list below to follow when planning your garden.

Crop Isolation Distances Self or Cross Pollinator

Beans 45 ft Self pollinator

Lettuce 45 ft Self pollinator

Peas (garden varieties) 45 ft Self pollinator

Peas (southern varieties) 80 ft Self pollinator

Peppers 45 ft Self pollinator

Brassicas examples 600 ft cross pollinator
cauliflower, kale,
cabbage, mustard,
collards, Chinese
cabbage, radish,
(kale, broccoli,
cauliflower, mustards
cabbage, collards
radish, & others

corn 600 ft cross pollinator

spinach 600 ft cross pollinator

beets & chards 600 ft cross pollinator

carrots 600 ft cross pollinator

eggplants 80 ft self pollinator

tomatoes 30 ft self pollinator

cucumbers 600 ft cross pollinator

squash-summer and winter 600 ft cross pollinator
pumpkins, gourds, & cantaloupes

watermelon 600 ft cross pollinator

leeks 600 ft cross pollinator

So basically you need to layout what you want to plant and find out what plants to distance from each other, you don’t want to plant pumpkins and squash next to each other, you will need to go by distances. This is an important part of seed saving if you want to preserve your heirloom varieties and keep the highest purity possible and avoid hybridizing you plants. And if you accidently mix things up just eat your vegetables and start again next year.

Also another tip if you are short on space trying planting certain varieties every other year, for instance pumpkins one year then squash the next.

Happy Gardening!

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