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how to grow greenhouse marijuana

If you live in a climate prone to more clouds than sun, you may want to consider investing in auto-flowering seeds. These will flower in a set time rather than depending on sunlight to spark flowering.

Whether you’re raising cannabis as a cash crop or just for personal use, you have many options for where and how you grow it. It’s possible to grow pot outdoors, indoors or in a greenhouse or high tunnel.

In many ways, growing marijuana in a greenhouse or high tunnel offers the best option. An outdoor marijuana greenhouse or high tunnel lets you take advantage of some of nature’s benefits, like abundant sun, without having to kneel to nature’s bad side, like frost, storms and deer, rabbits and other pests.

Growing Marijuana in a High Tunnel or Greenhouse

First, let’s get some terminology issues out of the way. Greenhouses and high tunnels are similar but not exactly the same.

To help you get on your way, DripWorks is happy to provide you some basic tips on how to grow marijuana in a greenhouse or high tunnel.

Plants will usually begin to flower around the summer solstice, the longest day of the year. Flowering will continue for two or three months till they are ready for harvest.

Greenhouse vs. High Tunnel

You can start with marijuana seeds or clones. Whichever you choose, pick the highest-quality stock you can find. This is no place to pinch pennies. Dealing with a reputable company and getting top-notch genetics will help ensure a bountiful crop that’s high in quality as well as quantity.

Once you have purchased or built your greenhouse or high tunnel, you’ll need to decide where to put it. Generally, a spot with southern exposure is best. This will provide a steady source of growth-inducing sunlight to your plants. You may also want to locate your high tunnel or greenhouse in an inconspicuous spot to deter thieves, vandals and other troublemakers.

How to grow greenhouse marijuana

In this guide, you’ll learn why growing marijuana in a greenhouse can be effective and how to get started.

Benefits of growing marijuana plants in a greenhouse

Size and panel opacity: Aside from type and material, two other greenhouse considerations are size and panel opacity. When deciding on size, think about what strains you might want to grow and how tall they might get. A good general rule of thumb is to get a larger greenhouse than the one you think you’ll need. If you don’t need the extra room for equipment and maneuverability, you can always add more plants. As for panel opacity, clear might seem like the best choices but the sun beating down on your cannabis plants can lead to competition in young plants and hot spots later. Diffuse or semi-diffuse panels provide ample, even light, preventing hot spots, competition, and uneven growth. All that should equal better yields.

Growing marijuana in a greenhouse

Climate: In addition to protection from rain and wind, marijuana greenhouses can contain climate control equipment like dehumidifiers, exhaust fans, and heating and cooling systems. With the help of these tools, greenhouses can extend the growing season and allow for year-round cultivation.

How to grow greenhouse marijuana

As a grower it is important to monitor the pH levels of the water you use to feed your plants. pH is the measure of how “acidic” or “alkaline” something is on a scale off 1 to 14. “7” is considered neutral. Small sickly buds may be the result in part of improper pH levels. A cannabis grower can measure the pH of water sample using a special p tester drops or a digital pH pen. When the pH is within the correct range, the plants can get the most out of all the nutrients, and their buds will reflect it. If the pH at the roots is too high or low, the plant can’t properly absorb the proper nutrients.

Humidity and temperature affect each other. When it is warmer, warm air hold more water than cold air. For cannabis to grow nicely the temperature and humidity levels need to be in an ideal range for the plants to thrive. When the plants are in the seedling stage the humidity can be between 70% and 80%. Some growers will tell you that seedling and clones prefer the level to be from 65-70% humidity. The high humidity is necessary because the roots are not yet developed, and the plant will take in water through its leaves.

It’s tempting as a new cannabis grower to overwater your plants. Plants will droop and can drown and die in water. One simple way to know if the plants are dry is to stick your finder in the top inch of the soil and see if the soil sticks to your finger. If it does not stick, then it’s time to water.

It’s no surprise that heat from the lights will raise up the greenhouse temperatures to dangerous levels if you don’t have proper ventilation. In addition you will need proper inlet air coming into the greenhouse. One way to accomplish this is with one fan bringing air into the greenhouse, and one sending the air out of the greenhouse. The total airflow into the greenhouse affects the humidity.

Don’t Harvest the Cannabis Too Early

So you are growing cannabis in a greenhouse. Most of this information is nothing new unless you are new to cultivating cannabis. Here are a few recommendation to stay on top of during your cannabis growing adventure.

It has been said that new cultivators are apt to harvest the crop too early. If you harvest too early, when the trichomes are still clear, the THC will not be as strong. Ideally one should wait until a more milky color has filled half of the trichome heads.

How doe you monitor the humidity and temperature? Purchase a hygrometer and a thermometer. A digital unit with memory showing you the maximum and minimum values from the past is important.

Considerations When Growing Cannabis in a Greenhouse

As a new grower, don’t try to grow without sufficient light. Did you know that the plant yield is in direct proportion to the amount of light it receives? There are three types of lights:

Ventilating the Cannabis Greenhouse