Marijuana Grow Basics by Jorge Cervantes
Cannabis enters the vegetative growth stage after four to six weeks of seedling growth. Vegetative growth is maintained in most strains with 16-24 hours of light daily. Plants grow faster when they received more hours of light. Marijuana will continue vegetative growth a year or longer (theoretically forever) as long as it receives 18-24 hours of light every day.
During the vegetative stage, green leafy growth is rapid. Healthy plants will grow an inch or more daily. Strong, fast vegetative growth is essential for a heavy harvest. Plants that are stunted now should not be induced to flower because they will yield much less. hold them back until they are stronger. Proper levels of nutrients are important for fast-growing vegetative plants. Make sure you are following the manufacturer’s recommended dosage when fertilizing. Some plants can take much more fertilizer than others.
In general, pure sativa and sativa-dominant strains require less fertilizer. One of the best ways to learn a strain’s fertilizer tolerance is to experiment so that you will know exactly how much fertilizer this specific strain needs.
In general, pure indica and indica-dominant strains can take higher doses of fertilizer. Check with seed sellers and internet forums to learn more about which strains can take high and low doses of fertilizers.
When to Induce Flowering
After four to five weeks of vegetative growth, plants grow early male or female pre-flowers. Once these pre-flowers appear, plants are ready to enter the flowering growth stage.
Indoors you can control the life cycle of cannabis with light and dark. This light and dark cycle is called the photoperiod. Cannabis stays in the vegetative growth stage as long as it receives 18-24 hours of light. Fowering is induced with 12 hours of light per day. The 12/12 day/night photoperiod triggers most strains f cannabis flower.
The vegetative growth stage is only two to four weeks long in most strains when grown indoors. Plants should be from 12-18 inches at the end of vegetative growth. If they are taller, artificial light will not be able to penetrate the foliage to the bottom.
Plants will need to be flushed at the end of the vegetative growth stage and possibly once in between after three weeks. I like to flush plants with three times the amount of weak fertilizer solution as the amount of soil or soilless mix in the container. This will flush or leach out all the extra built up toxic fertilizer salts in the growing medium.
Mother plants enjoy a longer life from six months and occasionally as long a several years. Once a plant’s sex is determined at pre-flowering, it can become a mother, clone, or breeding male.