Plant Biology

The formation of the seed is a part of the process of reproduction in seed plants. Before becoming a seed saver, it is necessary to know a few things about the reproductive abilities of plants.

The flowers of most plants carry both male and female organs, often within the same flower.

Self-pollinating plants have functional male and female flower parts within the same flower. Such blossoms are referred to as perfect flowers. Fertilization in perfect flowers usually takes place within each individual flower and usually does not depend on insects or wind. Some self-pollinated plants, such as peppers for example, can also be easily cross-pollinated by insects and must be grown in isolation to prevent variety crossing. Examples of crops with imperfect flowers include peas, tomatoes, beans, eggplant

Many vegetables produce separate male and female flowers. Some plants have male and female flowers on the same plant, we call these monoecious (from Greek meaning one-house), and some have male and female flowers on separate plants, and we call them diecious (from Greek meaning two-houses). Such a plant are said to have imperfect flowers. Examples of crops with imperfect flowers include squash, cucumbers, spinach and watermelons. These varieties rely on insects, wind or water to move the pollen from the male flowers to the female flowers. 


Terminology

  • Perfect flowers – contain male and female parts. Self-pollination in these blossoms is common, but they can also cross-pollinate
  • Imperfect flowers – single male and single female flowers within the same plant or in different plants of the same type and variety. Cross-pollination is required. Hybrids are common
  • Self-pollination – fertilization in a single or perfect flower, usually called “true-to-type.” Examples of crops that produce seeds through self-pollination include tomatoes, lettuce, beans, and peas
  • Cross-pollination – fertilization occurs between two flowers. Hybrids are common. Examples of crops that produce seeds through cross-pollination include squash, spinach, zucchini, and kale
  • Open-Pollinated (OP) – varieties of plants that reproduce themselves naturally, through either
    • a) cross-pollination – between separate individual plants of the same species and variety via wind, insects, or water
    • b) self-pollination – between male and female parts within the same flower or between separate flowers on the same plant
    • Open-pollinated varieties produce seeds that resemble the parent and result from combining genetically similar parents  
    • The advantage of using open-pollinated varieties is that they maintain desirable traits indefinitely and can increase the local adaptability of the varieties to soil and weather conditions
  • Hybrid – a cross between two genetically distinct parent plants of the same type. F1 hybrids, “first filial” or the first generation after the cross, are more stable and help to produce high-quality yields. F2 hybrids, the second generation after the cross, grown from seeds saved from F1 hybrid plants, will not be uniform and will have numerous different types due to genetic segregation
  • Heirlooms – open-pollinated strains of carefully selected varieties whose seed lines have been maintained and passed down over generations

Here is a link to more information on Open-Pollinated vs. Hybrid vs. Heirloom Seeds.


How to Save Seeds

Easiest vegetables to save seeds from:

The following are self-pollinating and generally true-to-type varieties:

 

Intermediate vegetables to save seeds from:

  • Cucurbits
    • Squash, pumpkin, melons, cucumbers, zucchini
    • Plant only one of each species to prevent crossing
      • Honeydew or cantaloupe
      • Pumpkin or zucchini or squash
  • The cross between a Zucchini + Pumpkin = Zumpkin

Image result for pumpkin and zucchini cross pollination

Challenging vegetables to save seeds from:

  • Carrot family
    • Beets, parsnips, carrot
  • Brassica family
    • Kale, cabbage, Brussels sprouts, chard etc.
    • Imperfect flowers, reproduce through cross-pollination 
    • Brassicas cross-fertilize among varieties very easily
  • Any biennial plants that produce seeds in the second year, for example, kale


Seed Viability

Every seed has different longevity based on how it is stored. A general rule for typical* storage:

1 year:  onion, parsley, parsnip, salsify, oregano,

2 years:  dandelion, sweet corn, leek, okra, pepper, chives, leek, sweet corn

3 years:  asparagus, beans,  carrot, celeriac, celery, chervil, Chinese cabbage, kohlrabi, pea, spinach, strawberry, pepper

4 years:  beets, Brussels sprouts, cabbage, cauliflower, chicory, eggplant, fennel, kale, mustard, pumpkin, rutabaga, squash, Swiss chard, tomato, turnip, watermelon

5 years:  cardoon, collards, endive, lettuce, muskmelon, radish, watercress, dill, melon, spinach, basil, cucumber, artichoke

*cool, dry, indoors, and protected from insects and rodents