So you’ve sprouted your seeds and are looking forward to seeing your first crop flourish. Whether you have 4 plants or 400 plants, the road from seedling to a mature plant will be the same. Treating your seedlings right is important to prolific future growth. To that end, there are a few things about your seedlings that you need to know.
Where to put them, you might ask? The first consideration as to where you’re placing your seedlings is simple temperature. You’re shooting for a temperature of 22 to 26 degrees Celsius. It must be warm when the lights are off as well. You might want to consider a small heater with good temperature control for your grow room if the room gets chilly without the light being on.
Another consideration is lighting. Most people germinate and grow seedlings under the same metal halide, HPS or LED grow light that they use for the foliage growth stage. Personally, I like sprouting seeds and growing the first four inches under fluorescent lights. They have a soft, warm glow to them that seedlings love. While on the topic of lighting, seedlings should have a lighting cycle of 16 hours on, 8 hours off. The night cycle should be completely dark. No peeking during the night cycle!
The seed contains all of the trace elements the seedling needs for the first several weeks. If the nutrient you’re feeding your plants with is without trace elements such as iron, boron and manganese, the oldest leaves will die at the ends of the leaf. The tips will go yellow first, and then brown. They tend to slow down growth or stop growth altogether if you don’t catch the nutrient requirements early.
A seedling is considered to be an infant until it passes the 4 inch height, whether that takes 2 or even 3 weeks. Cannabis is a weed though, so that time may vary drastically depending on breed and environment. It is after the first 4 inches that I put my seedlings under the grow lamps where they will stay for the rest of their lives.
After this 4 inch height, the seedling will behave as a mature plant. Environmental impacts to a new plant at this time become apparent within 3 or 4 days of the problem, be it a nutrient or perhaps even a growing medium problem. The central stalk will grow wider and the leaves will grow noticeably on a daily basis.