Making and Using Plant Propagation Gel

Planting gel, sometimes called propagation or germination gel, holds moisture around a germinating seed so it doesn't dry out during its early growth stages. The gel makes it easy to plant small, difficult-to-handle seeds, like those of carrots (​Daucus carota​).

Plant propagation simply means plant reproduction. There are two different methods of propagating plants. One is termed sexual and the other is termed asexual. Propagation gel is only relevant for sexual propagation.

Sexual propagation in seed plants is the union of the pollen and egg. The genes of the two parents are used to create another plant. It occurs when pollen (male) combines with an egg (female) to create an entirely new individual plant. For example, pollen grains from a male flower land on a female plant's stigma, depositing chromosomes in the egg. A seed is formed from which a new plant can grow.

Sexual propagation is sometimes the sole viable method for propagation of a plant. In addition, it has other advantages in that it can be cheaper and quicker than other methods. It can also help the plant to avoid transmission of certain diseases.

Asexual propagation does not involve mixing male and female DNA. Rather, it involves cloning a new individual plant from a part of an adult plant. For example, taking a cutting and sprouting it is an asexual form of plant propagation. Others include layering, grafting, and budding.

Most home gardeners tend to use sexual propagation — that is, planting seeds — to create their new plants. Although it is possible to plant seeds directly in the soil, sometimes gardeners use a method of starting seeds called pregermination, in which seeds are sprouted before planting. While this can involve fancy equipment, it can also be done by placing seeds between moist paper towels to sprout.

When seeds are small and delicate, it is easy to break off the shoots after pregermination. One way to prevent this is by suspending them in a propagation or planting gel. This gel can be made at home with cornstarch mixed with boiling water until it reaches a thick enough consistency to suspend the seeds. The cooled gel with the seeds in it is placed in a plastic bag with a hole in it, then squeezed along a garden row. The planting gel keeps the germinating seeds moist until they get established in the garden soil.

It's not difficult to make the planting gel at home. Whisk cornstarch into cold tap water, adding 1 tablespoon for every cup of water and then bring it to a boil. Keep stirring the mixture while it's heating so that lumps don't form. Boil until the cornstarch mixture develops a thick, gel-like consistency. Allow the gel to cool to room temperature before using it.