"Flower may get all of the glory, but good growers know that the money is made in the veg room. Whether you are growing from seed or from a rooted clone, the steps you take during the early growth stages will set you up for success," says Stewart Maxwell in his latest article on Elevated Botanist. According to Stewart, your plant’s root and shoot structure can be shaped for less work during veg and higher yields at harvest time. Also, beneficial microbes can be introduced to form a relationship with your plants and protect them from disease. Moreover, seedling care will prepare your plants for more aggressive grow environments during the veg and flower stages.
Seedling growth conditions
Young plants need to be nurtured to achieve their full potential. Ideal growth conditions for seedlings include 65%-75% relative humidity and temperatures of 70-80 F (22-27C). You can use an inexpensive digital sensor to log temp and humidity (there is an app for that). If you really want to know how your plant is feeling, use a laser thermometer to take the leaf surface temperature.
Fresh air is required for photosynthesis, and smooth airflow through your plants will help to prevent disease. If you are growing in a tent, and your only climate control is an inline fan, a variable speed control will help you manage the climate.
Most indoor climates run too dry for seedlings, and a small humidifier can be a worthwhile investment. Misting seedlings can help with humidity, but liquid water on your plants provides an entry for disease and should be avoided.
For outdoor growers, a small greenhouse will give you a big head start on the season. If you are in a sunny location, all you need is an extraction fan to promote plant health. Light intensity is 30%-50% lower in greenhouses, and plants will usually benefit from supplemental lighting. If power is limited, a small string of incandescent lights will keep your clones from flowering prematurely during the short days of spring.
Seedling germination
You can help your plants get a healthy start before they germinate by soaking seeds in a .5 to 1% hydrogen peroxide solution. This will kill pathogens on the outside of the seed, provide oxygen to the embryo, and soften the seed coat for faster germination.
Seeds can be planted directly in large pots or in the ground, but growing in small pots for a few weeks has several advantages:
- Small root balls are easier to water correctly.
- Many plants can be grown in a limited footprint.
- Plants in small pots are easy to prune and train.
If you are growing a lot of plants, it is easier to sow seeds in small plugs or peat pucks and transplant them to pots when they are well rooted. Seeds do not need high relative humidity to germinate, so it is best to avoid plastic domes. Autoflower seeds are not tolerant of root interruption and should be directly sown in their final location or transplanted as soon as they are well rooted in a plug.
Seedling soil mix
Seedling mixes are made from natural fibers, like peat moss and coco coir, that allow for rapid air and water exchange in the root zone. Aeration is improved by adding perlite, pumice, or rice hulls to create an environment where roots and microbes will thrive.
Conventional growers will often start seedlings in a sterile mix. Organic soils contain probiotics that help to feed your plants and protect them from disease. Compost and worm castings provide available nutrients and billions of beneficial microbes ready to go to work for your plants. Fertile organic soils usually contain indigenous mycorrhizae. These fungi are highly beneficial for water and nutrient uptake by roots.
In addition to compost, a variety of soil amendments are used to build fertile potting mixes. These inputs provide essential macro and micronutrients to feed the soil microbes that feed your plants. Living soil doesn’t ship well, and the best potting soils are usually made from ingredients sourced in your area.
Root pests
If you start with a suppressive living soil and pay attention to irrigation, you will probably never have an issue with fungal root diseases. Insect pests are a different story. Soils provide a habitat for many insects at various life stages. Some of these are detritivores that consume organic matter, but others are herbivores that can emerge from your soil to feed on your plants.
Many pests can be killed while they are still in the soil by watering in predatory nematodes at transplant. These microscopic worms will move through your soil, consuming fungus gnat and thrip larvae. Predatory nematodes are inexpensive and happy to chill for a few weeks in the fridge, making them a practical biocontrol for small-scale growers to use.
If they survive the nematodes, fungus gnats will usually hatch and swarm on the soil surface a week or so after transplant. These pests feed on roots and can spread disease between plants. Swarming gnats can be knocked down with bioinsecticides containing BTI. This naturally occurring soil bacteria is safe for use in organic gardening.
Read more at elevatedbotanist.com