When is germination visible

Soon afterward, the embryonic root called the radicle emerges from the seed and begins to grow down into the soil.

At about this time the shoot plumule also emerges, and grows upward out of the soil. In most species , the food reserves that provide fuel for the seed's development are contained in the fleshy part of the seed.

In some seeds , this fleshy part is divided into two seed leaves, or cotyledons. Seeds having two seed leaves are said to be dicotyledonous; those having only one are monocotyledonous.

In some plants, the growth of the shoot carries the cotyledons above the soil into the sunlight, where they become more leaf-like in appearance while continuing to provide sustenance for the growing plant. On some seeds, you can see the scar, or hilum, that was left behind when the seed became detached from the mother plant similar to a human belly button. Hilum are most visible on bean seeds, where the scars as known as eyes—as in black-eyed peas.

Others are less noticeable and look like little nubs or dents on the seed coat. Inside the seed coat is the embryo baby plant , the endosperm nutritive tissue , the cotyledons leaf-like structures , and the beginnings of the root and shoot.

They are just waiting to be released! Germination occurs when all the proper variables are in place for that particular variety oxygen, temperature, light or darkness and the seed coat absorbs water, causing it to swell and rupture. The first sign of life comes from the radicle, a little white tail that eventually becomes the primary root of the plant.

The role of the radicle is to anchor the plant in the ground and start absorbing water. Once it absorbs water, a rudimentary stem emerges and the cotyledons start to unfurl, often taking the seed coat with them as they rise above the soil.

Cotyledons look like leaves but are actually not leaves at all. There can be just one cotyledon monocotyledon, as is the case with onions and corn or there can be two dicotyledons, which are the majority of your vegetables. The cotyledons feed the plant until all the nutrients are used up. You can see how these two varieties of tomatoes have the same cotyledons, but once their true leaves emerge, one seedling has the serrated edges typical of a regular tomato leaf while the other has the smoother lines of a potato leaf.

In general, it takes one to three weeks for true leaves to appear once the cotyledons emerge. The timeframe is dependent on the type of plant, as well as environmental factors like sunlight, moisture, and temperature. Cotyledons are always the first leaf-like structures to form when a seed germinates. Most cotyledons are nondescript and tend to look similar within a plant family. For example, tomato, pepper, and eggplant seedlings members of the nightshade family all start out with a pair of long, narrow leaves with slightly pointed tips.

On the other hand, radishes, broccoli, and kale members of the brassica family begin life with two stubby, heart-shaped cotyledons. Once the true leaves develop, they start to resemble actual leaves on the mature plant—just tinier versions of them.

True leaves grow above the cotyledons and take over the job of supporting the plant for the rest of its lifecycle. After the first few sets of leaves sprout and the roots dig deeper into the soil, the seedling draws energy from photosynthesis above ground and nutrients found below ground. This is when it enters its vegetative state, and your once-little seedling is on its way to sexual maturity bud, flower, fruit, and seed.

You can determine how long a seed is expected to last in ideal storage conditions by using this seed life cheat sheet. Or, you can do a simple germination test to find out how viable your seeds are. Anything less than 50 percent germination is probably not worth sowing in the garden, unless you have enough seeds to sow heavily.

Depending on the type of plant and other external factors such as available light, moisture, and temperature , it may take up to four weeks or more for a seedling to develop true leaves. Occasionally, you might find three cotyledons instead of two on your seedling.

Three cotyledons a condition known as tricotyledony are a genetic blip in the seed caused by a recessive gene. Chances are, the plant will go on to develop normally. If the seed is planted in soil, not all of the stages are visible since some occur underground. However, if seeds are started in water, or in a wet paper towel, all four stages of germination are easy to observe. Watch for a small sprout that emerges from the bottom of the bean seed. This is the main root of the bean and is called the radicle.

This stage is only visible if the seed is germinated above ground. Wait until the second stage of growth when the main sprout emerges from the top of the plant.