Secrets Greenhouses Don’t Want You To Know
Commercial greenhouses have perfected the art of growing plants. They successfully produce vast quantities of lush, healthy plants for us to enjoy all year long without fail.
Although some of these methods are only feasible on an industrial scale, I have worked in a professional greenhouse and will show you how you can easily replicate these techniques in your home.
Not only will these methods allow you to grow beautiful, greenhouse-worthy plants, but they can also make caring for your plants easier than you would expect!
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Light
What the pros do:
In a greenhouse, they use special paneling that allows diffused light in every wall and ceiling. These panels cut down the harshness of direct sunlight to prevent burning the plants but allows every plant to get an equal amount of bright light.
Many articles on the internet separate plants into different categories based on whether they like bright, medium, or low light; articles like these can confuse people about what plants actually want. In a greenhouse, EVERY plant gets the same amount of light. Different plants can survive in varying light levels but do best when given bright indirect light.
If you aren’t sure what bright indirect light is, here is a newsletter I wrote on the topic :)
What you can do:
Place it close to a window to replicate the amount of light your plant would get in a greenhouse. Not many of us have transparent ceilings, but putting your plant as close to the window as possible will give it the best chance of thriving.
If your window gets direct sunlight all day and you are worried about it burning the leaves, you can either move the plant slightly away from it or place a sheer curtain in front of the window to help diffuse the intense rays.
If you enjoy the look of plants spread throughout your house and not just all crammed in front of the windows, get a grow light! You can find grow lights for reasonable prices online, which can be an excellent substitute for natural light.
Drainage Drainage Drainage
What the pros do:
Every single plant in an industrial greenhouse will have drainage. The plants are watered until it flows out the bottom. There are even a large amount of plants that get bottom watered in huge troughs.
This large quantity of water does not damage the plant or cause “overwatering,” as some may think. Overwatering is not an issue when a plant is given enough light, air movement, and drainage.
What you can do:
This is an easy one! Make sure your planters have drainage.
When you water your plants, make sure you let the soil dry out, then water enough so water runs out the bottom of the pot. This ensures that all the roots get the water that they need.
As long as there is drainage and you allow the soil to dry before watering again, you should not have an issue with overwatering.
Automatic Watering
What the pros do:
Industrial greenhouses have automatic watering systems that water all the plants on a given schedule to keep them growing fast and healthy. They spend tens of thousands of dollars on these automated systems, so they don’t have to hand water thousands of plants every day.
What you can do:
You can replicate this easily with a self-watering pot! I have many plants in them, making it incredibly easy to keep them properly watered. There are many self-watering pots on the market these days but the best, in my opinion, are the ones with a fill meter that shows how full/empty the reservoir is.
Here is an example of the type I’m talking about. This is the exact pot I have my Chinese Money plant in.
If you decide to use a self-watering pot, Pon is the growing medium of choice. Below is a link explaining everything you need to know about Pon!
Insecticide for Pests
What the pros do:
After hours they are constantly spraying all the plants with insecticide to kill any pests that would thrive in a greenhouse. If there is an outbreak, it could ruin their entire inventory and reputation going forward.
Automatic spraying systems take care of this problem and allow for regular treatment of the plants.
What you can do:
You can easily do preventative maintenance on your own plants by regularly spraying them off in the shower, treating with an insecticide like Arber’s Bio Insecticide, adding systemic granules to your soil, or treating them with Captain Jack’s Dead Bug Brew. (I plan on writing an entire newsletter on this topic sometime in the near future, so keep your eyes open for that.)
If you have a lot of houseplants, it’s important to treat your plants to prevent an outbreak in your home. No one likes bugs in their house!
Air Circulation
Proper air circulation is a paramount factor in growing healthy plants whether the plants are planted outdoors or indoors. Good air circulation promotes water evaporation, transpiration, prevents condensation on the leaf surfaces, reduce the growth of fungal infections and rot, and helps in making their growing limbs stronger. (https://balconygardenweb.com/5-vital-tips-to-improve-air-circulation-for-houseplants/)
What the pros do:
As you can see in the picture below, there are fans set up throughout the greenhouse that run constantly or on a timed schedule to keep the air moving throughout the greenhouse. Stagnant air causes many problems for houseplants.
What you can do:
Make sure the air is circulating throughout your home using a ceiling fan, box fan, or even central air/heat.
If you have plants suffering from rot or fungal issues, moving them away from tightly packed areas like groups of plants or a cramped corner will allow more air to circulate around them.
Water Quality
What the pros do:
Greenhouses will filter and treat their water to ensure it’s pure and the Ph is balanced to their needs.
The greenhouse I worked at added sulfuric acid to their water to make it slightly acidic. Some plants will not absorb fertilizer effectively unless the water is acidic. This is a bit extreme to be doing at home, but I wanted to show the steps a commercial greenhouse will take to force that extra bit of growth.
What you can do:
Leave your water out overnight before watering. This allows some of the chemicals in your tap water to dissipate. Also, if you have very hard water in your area, you can use filtered water to prevent mineral buildup in your soil.
Extras
These are strategies greenhouses use for specific types of plants.
Cold snaps in the winter
They will open the vents in the winter to bring in freezing air to “shock” some of the plants. The shock prevents them from growing tall too quickly and keeps them bushy and more appealing to customers.
Dark hours for flowering plants
Some plants will flower best when given a specific amount of light. Some greenhouses have black-out blinds that can close to end the day early for the plants allowing them to provide an exact length of day for their plants.
Sulfur burners
After hours, a greenhouse can be a very toxic environment. They spray insecticide and use sulfur burners to release sulfur gas into the air. The gas surrounds the plants and helps fight off mildew and other fungal infections that can grow in damp conditions.
I’m just pointing these out to show you that greenhouses do some things that are not realistic for us to do in our homes. You should not feel bad if your plant doesn’t look like it did when you first bought it because these are the ideal conditions it was used to. There is always some adjustment your plant goes through when you first move it into your home.
Final Notes
I will be sending out another newsletter in the next day or two talking about a little project I’m working on, reviving a String of Pearls!
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This Week’s Happy Planter Submission
My collection as a college student. I got into it with my boyfriend, we habitually gift each other plants. I really want a greenhouse one day but I only have one window in my apartment right now.
The really tall skinny one in the blue and white pot is an inchworm plant, a senecio succulent that I got from longwood gardens, PA
Thanks for the submission, @GalVillain! I hope you get that greenhouse someday. For now, that shelf is a pretty good start :)
That’s all for now!
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Talk soon! Feel free to enjoy my content on Twitter until the next newsletter :)
-Houseplant Hobbyist
I think this is your best newsletter yet! I like how you explain what green houses do and what we can do "in the real world" to make our plants the best they can be! Great content!