After a plant has sprouted, it starts its vegetative growth stage. In this stage, the plant uses photosynthesis as much as possible, in order to grow as much as possible. This stage also sees the forming of grow tips – the areas of the plant used for cloning. These grow tips are located at the top of the plant, and also between every major internode.
All plants have some sort of vegetative stage. This is also called the growth stage, as the most physical growth takes place during this time. If you want to, you can grow the plants without a dark period, which will decrease the maturing time by 15-30 days. The plant will keep growing vegetative until it is forced to flower. Technically, plants can stay in their vegetative stage forever, although obviously you won’t get any bud if you let them grow forever. The plant can grow anywhere from 12” to 12’ before it must be flowered, so it’s really up to you. Obviously larger plants will produce more bud, but also keep in mind the extra time that goes into growing plants larger.
Vegetative growth requires plenty of water and even more nutrients. I recommend a 20-20-20 mixture of soil, ideally with traces of minerals. This is recommended for both hydroponic growing and normal soil gardening. RapidGrowth and Miracle Grow are both great brands for vegetative growth. Peter’s 5-50-17 or a similar plant food is better for the flowering stage, and when you start to begin the 12 hour light cycles that trigger flowering. Miracle Grow Patio is probably the best choice for vegetative growth, as it contains sulfur and magnesium, both of which aid in growth greatly.
While plants are undergoing vegetative growth, they can use as much light as you give them. I recommend at LEAST 18 hours per day of constant light, but 24/7 light works even better. There is no need for timers at this point, unless you want to keep your electricity costs down. Try not to go lower than 18 hours per day, and NEVER less than 13 hours, as that will trigger flowering prematurely.
When plants are young, they are flexible, but weak. You should use this limited period to help strengthen the plants. A good way to do this is to bend the stems back and forth gently. If you don’t do this, stems will grow spindly and weak, and won’t be able to support much bud. An oscillating fan is a good for plant strength as well, because it mimics wind, and lowers the humidity around the stems. It also keeps the overall heat level down, and provides fresh air for plants to “breathe”.
If you’re growing hydroponics, here’s a good solution to use (per gallon):
Miracle Grow Patio – ~1 teaspoon
Epsom salts – ½ teaspoon
Human urine (sounds weird, but can do wonders) – ¼ cup
Oxygen Plus Plant Food (also optional) – 1 teaspoon
This solution is ideal for vegetative growth, and insures your plants will get all the nutrients they need. The nutrients will help stimulate overall growth, as well as increase the strength of the roots. Another, alternative mixture is ¼ teaspoon of Peters 20-20-20 plant food per gallon of water, with oxygen or fish emulsion added. Fish emulsion smells very bad, so it’s recommended for outdoor or greenhouse growing, and not recommended for indoor grow ops.