Marijuana Seedlings

Now that your marijuana seeds have sprouted, what’s next?  How do you care for your little baby marijuana seedlings? Your germinated seeds must be placed in a more suitable growing medium if you have started them in paper towels, rock wool or peat pellets.

Seedling containers

How do you choose the right size for your marijuana seedlings? Marijuana plants can mature in containers as small as 12 ounce plastic drinking bottles. Conversely, some growers have gone as large as 30 gallon containers indoors. You would need a barn, warehouse or a greenhouse to adequately grow such a plant as it will become a small marijuana tree. The average range is generally 1 to 3 gallons.

Some growers place the seedlings directly into the growing container that it will eventually flower in. The main benefit of this is that the plant suffers no transplant shock. However, the preferred method is to do several transplants from small to medium to large containers as the marijuana grows in size. There are several reasons for this:

1. Small planters utilize your space better
2. Small planters grouped together are the most efficient way to use your grow light source
3. A small container keeps the roots together and is easier to feed and water.

Some seasoned pros use their own mix. This is not recommended for the novice. Soil blends from hydroponic stores specifically designed for marijuana are your best – and often the most expensive option. Seed-starting soils from your local garden center or home improvement store will work fine. Such soils have enough fertilizer to carry you to the next stage. Some growers mix in additional perlite to better aerate the soil. Perlite is an  airy, white, volcanic pellet and available at most garden shops.

Planting your marijuana seedlings

Place garden soil in your container up to about 1” from the top. Pack lightly. Make a hole with a pencil, eraser-side down about ½” deep and put in your germinated seeds, root side down and cover with soil. If your seedlings are already in a seed-starter of some sort, simply bury them in the dirt and cover with ¼ to ½” of soil. Water until the soil is damp, not soaking. It is not necessary, but some marijuana growers like to give the young plants some support. Long wooden kitchen matches (minus the head) work well.

Watering and feeding your seedlings

During this phase, feeding or the adding of nutrients or fertilizer will not be necessary unless you have chosen a soilless mix. Watering should be done perhaps twice per day with a misting bottle for the first few days. How often you water will depend greatly on temperature and humidity. Once the marijuana root is better established, you can slowly cut back to watering every 2-3 days. If you are not sure, you can test by placing your finger into the soil. If it feels dry, then add water. It is important to note that the number one cause of early crop failure is overwatering. Wilting or drooping leaves on your plants are a sign that your plant is thirsty. Plants will revive quickly from such dehydration.

While many gardeners use tap or well water, the more sophisticated growers use reverse osmosis, filtered or bottled water and adjust the pH (acidity/alkalinity) of the water.  If you are using municipal tap water, fill a bucket or a reserve reservoir and let it sit for several days. This allows most of the chlorine present in the water to evaporate.

DO NOT water directly on the plant. They are very delicate at this stage and the stem and roots are easily damaged. Water around the seedlings a few inches base of the plant. It is best to water your plants first thing in the morning for best uptake.

Marijuana seedlings lights

Marijuana seedlings require very little light and can be grown under CFLs (spiral compact fluorescents), tube fluorescents, LEDs and the blue light from Metal Halides (MH). Stay away from incandescent lights as they put off too much heat and too little light. The higher the Wattage your light source, the further away it should be from your seedlings unless you are using LED grow lights with good ones running nearly cold. Too far away and the plants will stretch towards the light making them weak and spindly. Too close and the bright light and heat may damage them, except with LEDs.  Let us say you are using fluorescents or LED grow lights. It would be fine to place the light a foot above your plants to start and give the seedlings a chance to ‘harden up’. If they react favorably, you may lower the light a little bit each day until the lights are maybe 4” above your plants.

Blue light dominant LEDs and full spectrum LED grow lights offer an excellent start, lower electricity costs and very little if any heat.

High Pressure Sodium (HPS) lights are generally not used for seedlings as they do not require the amount of light that HPS puts out, and more importantly, HPS is deficient in blue light. Blue light is what plants use to point them towards the light source. This is called phototropism.

Have fun and good luck growing out your marijuana seedlings!