The Effects of Boiling Seeds on Germination

Purpose of Pretreatment

• The main idea behind any pretreatment method is to reduce the resistance of the outer seed coating and allow the embryo of the new plant to grow through easily. By softening the outer coating, pretreatment helps to speed up the rate of seed germination. There are many other types of pretreatment besides the use of boiling water. These include abrasion of the seed coat, passing the seed through the gut of a mammal or bird or fire scorching.

Effects of Boiling Water

• The use of boiling water produces distinct effects on the seeds. These include softening the very hard outer covering of many seeds. Many seeds are naturally coated in a hard wax. This is dissolved by the exposure to hot water, consequently allowing moisture to permeate the seed and allow it to germinate. Once the seeds are ready for sowing, they are usually visibly swollen and may easily be cracked with a fingernail. On a general note, seeds that are heavier or those with a thick, stony coating benefit from the hot water treatment. Lighter seeds and those with light coatings usually germinate well enough without any pretreatment.

Method

• Place the seeds in a large bowl and pour boiling water over the seeds. Let the seeds soak in the water overnight. Check the seed coat in the morning with a fingernail to see if it has softened. If the coat is still very hard, repeat the step again. You may have to repeat the process several times for certain seed coats to soften. Drain the seeds and wash with cold water to remove any waxy residues.

Planting

• Most seeds require planting right away while they are still soft and wet. If not immediately planted, the seeds are prone to encourage the growth of fungus. In case the seeds are not intended for immediate planting, dry the seeds by spreading in a single layer on a tray. Place in a warm, dry place to minimize the risk of fungal growth. Check carefully to see for any signs of fungus before storing in an airtight container or plastic bag.