Managing Vegetative Growth Time Indoors
How long a crop needs to remain in the vegetative phase can depend on several factors, including whether the crop is from clones or seeds. The general idea is to grow vegetatively until the canopy space is of a sufficient minimum fullness to allow the flowering phase to take over and fill the rest of the available canopy space during flowering. If flowering is started too soon the grow space may not be as full at harvest time; if started too late the space can become overgrown during flowering.
Growers have more control over vegetative time than over flowering (maturity) time, because flowering time is a genetic issue where vegetative time is a management issue. Aside from controlling light intensity, there are two ways to minimize crop time via the vegetative phase.
- Use of a separate vegetative grow area
- Adjusting plant numbers
Separate Vegetative Grow Area
A separate dedicated vegetative grow area allows a grower to limit crop turnover time to only the maturity time of the strain being grown, without adding any additional crop time for the vegetative phase. While one crop is maturing the next can be started at the same time, thus the vegetative phase for the next crop is being run concurrently while the flowering crop is still maturing. Scheduling the time at which the vegetative plants are ready to be flowered and the time at which the harvested flowering space becomes available is a challenge.
Adjusting plant numbers
Because vegetative time is determined by the fullness of the canopy, the length of time depends on the size of the plants being grown. The larger a plant needs to be, the more time it will take to grow. Given the same space, growing fewer plants will require a longer vegetative time than growing more plants, because each plant will grow at the same rate regardless of their numbers. For example, in an 8 square foot space it might take 6 weeks to vegetate 1 plant until it's large enough to be flowered, where using 3 plants could fill the same space in 2 weeks. The need for any vegetative time could be eliminated completely by increasing plant numbers further. Using 8 or 16 plants, for example, may eliminate the need for any vegetative time. This doesn't need any additional lighting or space for a separate grow area, but could require propagation space to be expanded to hold more plants. Plant numbers bring legal concerns to some growers, making the choice between his gardening convenience and his legal concerns is a challenge.
- Don't need to be sexed
- Have the same growth traits (for predictable growth and maturity time).
- Will all have the same prized traits as the female they were cut from.
- Have no minimum wait-time before they can be flowered
(Unlike seed plants, clones don't need to be vegetatively matured coming from a mother plant that already spent time doing so. For all intents and purposes clones are the same chronological age as the seed plant from which they originated.)
For those reasons most experienced growers use clones. However, one must start somewhere, and seeds are usually the choice for a first crop.
While contemplating your target production it would be a good idea to keep your mind open to both options because you may start your first crop with seeds and your second with clones from its best female. Unlike clones, seed plants are grown until they are both large enough to have sufficiently filled a space and to have vegetatively matured enough (chronologically) to have a fast flowering response upon induction (flowering photoperiod). But because these points in time don't always coincide, allow for about four weeks of vegetative time (at a minimum) when figuring your target production with seed crops.