Germination of Cannabis Seeds
Cannabis seeds needs only water, heat, and air to germinate. They do not need extra hormones to germinate. Seeds sprout without light in a wide range of temperatures. Properly nurtured seeds germinate in two to seven days, in temperatures from 70-90 degrees Fahrenheit. Temperatures above 90 degrees impair germination. At germination, the outside protective shell of the seed splits, and a tiny, white sprout (radicle) pops out. This sprout is the root or taproot. Cotyledon, or seed leaves, emerge from within the shell as they push upward in search of light.
Seeds are prompted to germinate by:
- Water
- Temperature
- Air (oxygen)
Timeline for Germinating Cannabis Seeds
55-72 Hours- Water is absorbed, root tip (radicle) is visible
10-14 Days- First roots become visible
21-30 Days- at least half of the seeds should be rooted by day 21, and seeds not rooted by day 30 will probably grow slowly.
Water
Soaking seeds in water allows moisture to penetrate the protective seed shell within minutes. Once inside, moisture continues to wick in to activate the dormant hormones. In a few days, hormones activate and send enough hormone signals to produce a radicle. The radicle emerges upward to bring a new plant into the world. Once a seed is moist, it must receive a constant flow of moisture to carry nutrients, hormones, and water so that it can carry on life processes. If germinated seeds suffer moisture stress now, seedling growth will be stunted.
Temperature
Cannabis seeds grow best at 72-78 degrees Fahrenheit. Low temperatures delay germination and high temperatures upset seed chemistry causing poor germination. Once germinated, move cannabis seedlings to a slightly cooler growing area, and increase light levels. Avoid high temperatures and low light levels, which cause lanky growth.
Air (oxygen)
Seeds need air to germinate. Moist, soggy growing mediums will cut off oxygen supplies and the seed will literally drown. Seeds germinate poorly when planted too deeply. Tender seedlings do not have sufficient stored energy to drive through deep layers of soil when sprouting. Sew seeds twice as deep as the width of the seed. Plant a 0.125- inch seed 0.25- inch deep.
Household water contains enough dissolved solids (food) to nourish seeds through their first few weeks of life. Although seeds need only 30-50 ppm of nitrates before they germinate, any more will disrupt internal chemistry. Some growers choose to use distilled water that contains practically no dissolved solids to germinate seeds. In fact, a high concentration of dissolved solids (salts) in the water will actually pull moisture out of the seed!
Start feeding two to four weeks after seedlings have sprouted. Some growers wait until leaves yellow to begin feeding. Use a mild quarter-strength solution. If yellowing persists, give seedlings a little more fertilizer. Some seeds have a very hard outer shell, testa, and must be scarified to allow water to penetrate. To scarify, line a matchbox with a piece of fine-grain sandpaper or emery board. Put the seeds in the matchbox and shake for about thirty seconds. Then, remove the seeds, and make sure they have been scuffed a bit. Just a little scuffing will allow water to enter and set germination in motion.
