Seed Exploration & Plant Propagation

Every seed contains three fundamental anatomical structures:

1. Seed Coat (Testa): Tough outer skin protecting against insects and drought.

2. Cotyledon / Endosperm: Stored food (starches, proteins, lipids) that fuels early growth.

3. Embryo: The baby plant complete with a miniature root (radicle) and baby leaves (plumule).

Step 1: Take a large lima bean or kidney bean that has soaked in water overnight.

Step 2: Carefully peel away the softened, wrinkled seed coat using your fingernails.

Step 3: Gently pry the two halves of the bean apart along their natural seam.

Step 4: Use a hand lens to locate the tiny curved embryo resting inside—you can see tiny embryonic leaves and a root tip!

Germination begins with imbibition: the dry seed rapidly absorbs water, swelling up to double its size and cracking the seed coat.

Enzymes activate, converting stored starch into glucose. Cellular respiration surges, requiring high amounts of oxygen. If soil is waterlogged with zero air, the seed suffocates and rots.

Many native Alaskan wildflowers and trees (like lupine, fireweed, and birch) have a built-in safety clock called cold stratification.

If seeds germinated in autumn, the first freeze would kill the tender seedlings. Instead, chemical growth inhibitors in the seed coat only break down after enduring 60–90 days of cold, moist winter conditions!

Students compare seed sizes: tiny carrot seeds (requiring shallow sowing) vs large pea seeds (planted 1 inch deep).

We discuss how starting seeds in greenhouse cell packs in April ensures robust transplants ready for the rich soil beds of Tyonek Grown.