When and How to Trim Hemp Plants

The science of plant horticulture focuses on both the aesthetics of plants; how they appear, and on the plant’s development. It is an applied science, intended to alter, control, and enhance how the plant grows; but more importantly, how the plant performs. The horticulturalist partners with nature in determining the plant’s rate of growth and pattern of growth. Horticulture focuses on issues such as planting, watering, nourishing, lighting, and trimming.

Plants can benefit in many ways from proper trimming. In the case of the cannabis plant, if you were to leave one untrimmed throughout its growing cycle, it would grow straight up, with little lateral growth. This may be desirable, or it may be undesirable. If you’re growing outdoors, there is usually no issue with the plant’s height, unless its height makes it difficult to harvest flowers.  Cannabis plants can grow as tall as fifteen feet outdoors in direct sunlight. One benefit of an outdoors, untrimmed plant is that sunlight can reach all of the areas of the plant evenly, unless the plants are grown too closely together.

However, a fifteen-foot tall plant may be undesirable, for both indoor grows and outdoor. Indoors, you may have ceilings as low as eight feet, or lower. Even when growing outdoors, a grower may want to keep the plant’s height under control, especially if there is an issue with curious neighbors, or due to state and local ordinances pertaining to cannabis grows.

When trimming plants, it is important to understand some basics. First of all, you should select a trimming tool that is sharp and clean. You want to make a clean cut in order to minimize trauma to the plant. Also, it needs to be sanitized, preferably with alcohol, so that the tool doesn’t introduce any disease-causing contaminants to the plant. A good set of rose trimmers will work nicely, but a hardy set of scissors may work as well.

Every plant has a finite amount of energy available to use in its growth. A grower should therefore ask himself, “How do I want to concentrate and direct this plant’s energy in order to maximize and enhance its growth and production?”

Removing dead or diseased plant material, like leaves and stems, is therefore a necessary first step, because this material will sap vital energy away from new growth. Every time you trim material off of a plant, it stimulates growth in other areas of the plant. After each trimming session, water the plant with plant food. Always leave at least two days between trimming sessions for recovery.

During the earlier stages of plant growth, try not to trim the big, green leaves. These leaves are sugar producers, and play a key role in plant growth.

Trimming is an important component to growing cannabis, and is done for various reasons:

1.    To control the height of the plant

2.    To control the breadth of the plant

3.    To remove dead or diseased leaves

4.    To remove dead or diseased stems

5.    To introduce light to all areas of the plant

6.    To encourage the growth of the plant’s structure; leaves and stems

7.    To encourage the growth of the plant’s flowers

8.    To increase the size of the plant’s flowers

9.    To increase the number of flowers produced by the plant

10. To direct the growth of the plant in a particular area or direction

Anytime you make a cut on the stem, you want to make it just above one of the plant nodes. A plant node is a nob or point of fattening on the stem. Nodes are points of potential new growth. When you trim just above the node, the node can now generate new stems, leaves, or flowers. You can also generate a new root system off of a node in a greenhouse.

If you want to control the plant’s height, it will have to be topped, at least once. The top of the cannabis plant is its principal growing point. When you top a plant, now instead of one vertical stalk, you will have two. Before topping your young plant, it is best to wait until it has developed three or four sets of leaves. If you top it a second time, you should again wait until the plant has had some time to establish new leaves and stalks.

Instead of your plant growing to fifteen feet, now it will grow to about seven or eight feet. If you allow the plant to develop a little more, and then top your two stalks again, now your plant will only grow to about five or six feet in height. However, it will be bushy, and you’ll need a larger planting footprint, because the plant will consume more lateral area.

There is also a growing point at the end of each stem. When you trim a growing point, two new stems will grow off of the node.  This will result in shorter stems, or a shorter plant height if you top the main stalk. It will also result in a bushier plant with denser leaf foliage.

A bushier plant may be undesirable because it makes it more difficult for light to reach the interior of the plant. Therefore, when trimming growing points, it should be done in a strategic manner, so that light can still penetrate the plant and reach all of the leaves.  Over-trimming can result in a light-starved, stunted plant.

Once a cannabis plant begins to flower, you should cut back on the trimming, because the plant requires energy to recover from trimming. After your plant has been flowering for two weeks, you should cease trimming altogether.

Trimming Techniques

These are some of the traditional trimming methods used by cannabis growers. Bear in mind, that the more trimming you do on the plant, the longer the plant’s growing cycle is, timewise.

TOPPING –

Topping has the effect of producing more branches, with more leaves. Ultimately, this will translate into more flowers and a higher yield.

FIMMING –

Fimming is similar to topping, except that instead of completely removing your growing point above a node, you give the growing point a ‘haircut’.  Pinch the leaves of the growing point between your thumb and finger and then slice cleanly through the leaves, leaving about 25% to 30%. This will result in four buds generating off of the cut, and will greatly enhance your final yield.

LOLLIPOP TECHNIQUE –

This name derives from the shape of the plant, after the lollipop technique has been applied. Simply put, the lollipop technique involves removal of all plant material near the base of the plant. Now you have just bare stalks near the bottom. This focuses plant growth near the top of the plant, resulting in a lollipop shape to the plant.

These lower parts of the plant are of no use anyway, once the plant reaches a certain stage of maturity. Make sure you complete the lollipop cuts prior to the plant flowering.

FINAL THOUGHTS

If you’re growing multiple plants, try several trimming techniques to see which one works best for you. Be sure to keep one or two untrimmed control plants to compare with your trimmed ones.