Saturday, February 25, 2012
Sunday, February 5, 2012
INTRODUCTION TO HEIRLOOM GARDENING AND SEED SAVING
I have realized that there are some things that you need to be introduced to before you can plan your heirloom gardens and select your seeds. We will be going into these concepts in depth in the classes, but I’d like to give you some basic information now to help you plan your garden and make your seed selection.
Here is a quick guide to the difficulty of saving seeds from various species.
Easier species: Peas, tomatoes, beans, lettuce, tomatillos, squash, eggplant and potato(no pollination)
More difficult species: beets, spinach, cucumber, onion, pepper and turnip.
Most difficult species: watermelon, carrots, melons and corn. Melons need to be hand pollinated and it is very difficult to distinguish between the male and female blossoms. Corn needs to be planted in volume of at least 100 plants. You need to collect pollen from 50 plants and use it to pollinate 50 other plants, this prevents inbreeding depression.
For many plants, you will not be able to save any pure seeds if you plant multiple varieties of the same species. If you do, you must be able to isolate these varieties from each other by one of the methods described later. If you would like to change your seed requests, please let me know.
The difference between heirloom and hybrid seeds.
Heirloom seeds have reproduced plants identical to their parent for many generations, and if properly protected, will continue to do so indefinitely. Varieties are protected and reproduced year after year. You can save and plant these seeds every year and get the same produce.
Hybrid seeds are from plants that experienced cross pollination either purposely or naturally. Hybrid seeds will produce plants that are different from their parent. You can only reproduce the same hybrid by crossing the same identical original plants. You cannot plant the seeds of hybrids and get a plant that resembles its parent. Most commercial hybrid seeds restrict you from saving seeds, or have sterilized the seeds, so you have to buy seeds every year.
Heirloom seed saving requires extra effort in order to prevent cross pollination. In order to understand how to prevent this, an understanding of how plant pollination works is required.
There are three ways that pollination occurs, Wind Pollination, Insect Pollination and Self Pollination.
Pollen is dispersed by the wind. The purpose of the wind is to shake the pollen from the tassel onto the silk, but pollen is very light and can travel several miles on the wind, crossing it with other gardens. It is difficult to isolate wind pollinated plants by distance, and more difficult methods must be used. Corn, Spinach and Beets are in this category.
Many plants produce both male and female blossoms on the same plant. The male blossom is on the end of a long straight stem and has an Anther that produces pollen ready to be picked up when the blossom opens. The female blossom is on the end of a miniature fruit and has a Stigma that receives the pollen and the fruit or vegetable matures. Insects such as bees, transfer the pollen from the Anther to the Stigma. These varieties must be hand pollinated or isolated to keep the variety pure. Squash is familiar insect pollinator.
These plants have functional male and female blossom parts within the same blossom. Pollination occurs within the blossom. Some beans are pollinated within the blossom and it never opens, eliminating the possibility for cross pollination. Others, such as peppers, self pollinate, but then the blossom opens which allows cross pollination by insects.
METHODS FOR MAINTAINING PURE VARIETIES
Please note that you do not have to have all of the produce from a plant pure, only enough of them to save the seeds. The produce that is pure and is for seed saving must be marked clearly.
There are 4 methods that are used to keep seed pure.
The distance isolated must be large enough to prevent contamination by insect or wind blown pollination. This distance will vary from species to species and is referred to as the “isolation distance.” You do not want to grow a different variety of a species in the same spot, seed from the previous variety will have dropped and will grow and cross with your current variety.
Annual Varieties that cannot be isolated by distance can sometimes be isolated by time. This can be done by planting the first variety as early as possible. Then the first crop begins to flower, sow the second variety. Time isolation will only work if the first crop sets all of its seeds before the second crop reaches the flowering stage.
This can include bagging, caging or alternate day caging.
This technique is used mainly for vegetables that are insect pollinated but can also be used for some crops that are wind pollinated. This involves transferring uncontaminated pollen from a male blossom onto the receptive stigma of the female blossom which has also been protected from contamination. After the female blossom has been pollinated by hand, it must be protected from contamination.