growing weed in a greenhouse

Greenhouses also provide cover for your plants, as heavy rains will damaged them and cause them to rot if too much moisture is trapped inside the buds. Some can also have dehumidifiers, heaters, air conditioners, and fans, all of which will also regulate the climate.

A common practice among greenhouse farmers is to run cycles of plants known as “light deps”—short for “light deprivation”—during the summer season. By cutting off the amount of light a cannabis plant gets before the end of the season, you can trick it into flowering early. This will allow you to pull a crop early, which is key if you live in a climate that gets cold and wet early in the fall—you’ll want to harvest before the rain sets in and causes your buds to get moldy.

If you want to continue growing cannabis through the fall and winter, you will have to lean more heavily on supplemental lighting and heaters.

Controlling your greenhouse climate is essential to producing a quality product. Some greenhouses have windows or paneling that can be opened or removed to either allow for wind circulation and to cool plants, or to trap in heat.

Supplemental lighting allows the grower to extend the hours of daylight and to improve the quality of light on overcast days. This will give you more control over the vegetative state of your plants.

Weather and Climate Control.

On a hot day, you experience the science behind a greenhouse when getting into a parked car that has been left in the sun.

They also allow for year-round cultivation, climate control, and a controlled exposure to sunlight. What’s more, they’re cheaper than growing indoors and produce a more consistent product than fully outdoor grows.

This greenhouse effect opens up the door to year-round cultivation, but cannabis still needs light from the sun in addition to the warmth that a greenhouse provides.

Advanced greenhouses can allow you to grow year-round by controlling light. They can provide supplemental lighting when it’s too dark outside and they can block out all incoming light if it’s too light outside.

During the winter solstice in Seattle, for example, there’s less than nine hours of daylight, and the light that is available is low in the sky and poor for growing. This light and energy will still help heat the greenhouse, but you would need to use supplemental lighting to extend the hours of light in the day in order to get a quality product.

Once cannabis starts getting 12 hours of light or less, it’ll start flowering and producing buds. This happens outdoors at the end of summer, when days start to get shorter.

Greenhouses are a great, inexpensive way to cultivate cannabis. They harness the power of the sun, provide a warm climate, and protect gardens from harsh environmental conditions.

Solar radiation (energy from the sun) passes through the transparent walls of a greenhouse and heats up soil and plants, keeping a greenhouse warm even when the outside air temperature is cold.

In turn, soil and plants release energy as infrared radiation, which can’t escape the greenhouse, so the trapped heat warms the air.

Cannabis generally goes in the ground outside between April and July, when the sun is out for most of the day. This keeps plants in the vegetative stage.

Manipulating Life Cycles.

The ability to control light and keep the climate stable will allow for year-round cultivation just like indoor growing. But growing outdoors and with a greenhouse is a lot more inexpensive than growing indoors, and you’ll save a lot of money on electricity costs. Even if you need to supplement light in a greenhouse, it’ll still be cheaper than the energy needed to power an indoor operation.

Lighting Control.

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.

Generally, two basic options are available for growing your pot plants. You can grow each marijuana plant separately in its own container, or you can put the plants in the ground. Using containers will make the plants easier to work with and to move if you want to transplant them.

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.

Greenhouse vs. High Tunnel.

Like greenhouses, high tunnels shelter plants from the elements. They differ from greenhouses, however, in that they are more passive. Generally, greenhouses provide heat and ventilation through electrical systems, while high tunnels rely on passive ventilation systems for moving air and on the sun for providing warmth.

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.

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.

Many folks in northern latitudes start their seeds indoors in April under grow lights and transfer them to a greenhouse in May. Your own schedule will depend on your climate and growing season, of course.

You will want to be sure to give your cannabis plants adequate amounts of water and fertilizer to ensure steady, strong growth throughout the season. A drip irrigation system can supply these essentials reliably and economically. DripWorks.com has an entire section on the best irrigation products to grow cannabis.

Growing Marijuana in a High Tunnel or Greenhouse.

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.

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.

Of course, that means high tunnels cost significantly less than greenhouses. How much less depends on the options you are looking for. A variety of high tunnel greenhouse kits and traditional greenhouse kits are available for purchase. If you are handy and looking to save, you can also assemble your own high tunnel or greenhouse with some basic materials.

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

Consider Your Location.

We hope this basic greenhouse marijuana growing guide has been helpful. If you have any questions, feel free to call the irrigation experts at DripWorks toll-free for advice you can trust.

Ventilating the Cannabis Greenhouse.

Once the plant is in the vegetative stage, the humidity should be between 40% and 70%. The humidity needs to be lowered by 5% each week. The temperature can also be increased a bit because the roots are now absorbing more water, and evaporation is occurring through the leaves which cools the plant.

Once the plant is flowering, the humidly needs to be lowered to 40-50%. This is considered critical by some growers. At this time you may lower the ambient temperature. With the lights on a good temperature range is 68 to 78.8 degrees Fahrenheit.

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:

One to two weeks before the harvest, consider bringing the humidity levels down as much as possible in the 30-40% range.

Ample Light.

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.

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.

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.

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.

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.

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.

Too often novice growers handle the seed too much when they are trying to germinate which can accidentally kill them before they have the opportunity to sprout. Seeds can take as long as 10 days to sprout. Patience in this case is a virtue!

Monitor the Temperature and Humidity in the Greenhouse.

Overwatering in the greenhouse.