Isolation is important in the growing of an open pollinating crop for any purpose. Even if your plan is not to save seeds from your crop, the fruit of a plant is the offspring of its parents and let me tell you some strange combinations can occur.
From experience I can tell you that if you grow cantaloupe too close to cucumber, you will wind up with cucaloup. They look like cantaloup on the outside and cucumber on the inside, but while you might think its a great sandwich slice, chances are you will find them as disgusting as we found them. We’ve learned out lesson and do not grow them anywhere near each other. The thing is, unless you are seed saving, most potential cross pollination will not result in disastrous results.
If you grow two varieties of zucchini next to each other, chances are great there will be some cross pollination. A few of your zucchini will not look exactly as you thought they should. But chances are you will loose much more to pests than to the occasional cross pollination that creates a monster like the cantaloup. The same is true of most cultivars. You try to plant them apart, but if there is an occasional mixing it is not all that much of a bother. In fact, sometimes it is a happy mistake. One of the sweetest water melons I have ever grown was likely a cross between a Stars n Moon variety with a Jubilee Bush water melon. It had the look of Stars n Moon, the size of the Jubilee Bush, but a sweetness of nearly pure sugar. It also seemed to have built in refrigeration. Although I know this is impossible, it seemed cooler than other water melon we harvested on the same day. Ever since, I have been sure to plant the two varieties right next to each to each other but thus far the happy accident has not repeated itself.
Isolation and Seed Saving
When you plan to seed save, you are faced with an entirely different set of goals. If your intent is to grow heirloom seeds, you must isolate various plants to prevent cross pollination. Hot peppers are one of those plants called open pollinating plants.
Contrary to the popular use of the term ‘open pollinating’, what the term indicates is that the flower opens and the female parts can be pollinated by pollen from many sources. You might recall the story of the birds and the bees that your parents told you in their attempt to describe sexual procreation. Open pollination contrasts cleistogamy which is a system of reproduction where the flowers do not open. A cleistogamy system of reproduction is often called self pollinating. However, that does not mean that an open pollinating plant is not self pollinating.
In isolation, an open pollinating plant such as the chili pepper can self pollinate with assistance of nothing more than gravity. Its flowers produce both male and female parts. While wind, insects and physical manipulation can help aid in pollination, gravity alone will cause pollen to fall and contact the necessary female parts. However, compatible pollen from other plants will be carried by the breeze and insects to combine its dna with what ever it can. This results in cross pollination and both fruit and seed stock becomes different from its parents. So if seed saving, you really should make an effort to isolate the plants you plan to harvest from seed.
How the Big Dealers do it
There are many ways to isolate a seed crop which are available to the small farm / homestead that are not practical for large scale seed producers. One popular large scale method is to grow single varieties on any particular plot of land. Although wind and insects might bring pollen from other fields, this method is surprisingly efficient and effective. The challenge is when you do not have entire fields isolated from one another to grow. When you are growing at a homestead or backyard level, other techniques must come into play. It is a lack of those practices which tend to pollute the genetics of various seed saving efforts.
Small Scale Seed Saving
Fortunately, there are techniques available to the small scale seed saver which are even more effective than simple crop isolation. In fact, when properly technique is applied the heirloom seeds produced by small scale farmers can exceed the genetic purity of larger growers. Instead of isolating entire fields, the smaller grower can isolate individual plants and even portions of individual plants.
In her book, Seed to Seed, author and fellow seed saver Suzanne Ashworth discusses some of the many affordable techniques available to the smaller seed saver. Simple approaches like putting a plastic bag over the flowers of your favorite plant make it easy for even the smallest scale grow to maintain genetic integrity.
Our personal favorite is small portable green houses. When the season begins, we use these the way one would a cold frame to protect young plants. As the season progresses, we either open or remove the mini green houses such that the plants can receive full sunlight, wind, and a more natural environment to grow in. When it is time to be concerned with cross pollination, the mini green houses return to the best examples of each cultivar.
By using suggestions from this book, a bit of self ingenuity and some common sense: it is possible to grow many different varieties on a relatively small chunk of land without much concern for genetic contamination and cross pollination. However, keep in mind accidents do happen.
Selective Harvesting and Seed Saving
Even with the best safeguards, there is always a chance for cross pollination. Fortunately, many fruits will show the cross in their appearance and flavor. Not all mind you. Maybe not even most. That cucaloupe sure looked like a cantaloup from the outside. But the inside sure didn’t taste like either of its parents.
This is where selective harvesting for seed saving comes in. If a pepper does not look true to its cultivar, it goes into chili rather than your seed saving program. Although this technique certainly wont work 100% of the time, it does further improve on isolation.
Additionally, the practice of selectively harvesting for seed saving helps to improve your particular genetics. If you select only the best examples of a cultivar for your seed saving program, you will improve our genetics year after year. Each generation of seeds producing a crop that is closer to the cultivar’s purist form.
If you are so inclined, those happy accidents do not need to go into the chili pot. If they are not true to the cultivar, you do not want their dna to mix with what you save for that cultivar. But that doesn’t mean end the line. Just the opposite. If you are so inclined, why not grow it the next season and see what the seed yields. For all you know, God might have blessed you with a new cultivar. One which after the proper stabilization of selective breeding might be something for you to put your name on.
As a seed saver and heirloom perpetrator, you have a duty to reproduce and improve upon a true line. That doesn’t mean you must exterminate those things which do not grow true. In fact, the happy accidents are one of the reasons to seed save. Not just to refine, but to expand. Well, unless you’ve grown a cucaloupe.