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352-Greenhouse Hacks and Tips: Lessons Learned In My First Year

| Grow, Podcast

I just passed the one-year mark of being a greenhouse owner in January. It has been an eye-opener, and I have learned so much. I want to share with you the greenhouse hacks and tips and the lessons learned in my first year and the main “aha” moments.

It’s been amazing so far to experience the new opportunities owning a greenhouse presents. I know I’m just scratching the surface so far and will continue to learn. 

 

Joe Lamp'l and greenhouse

Celebrating my new Yoderbilt greenhouse.

 

My greenhouse is 12 feet by 32 feet. It’s by Yoderbilt, made of wood and poly, with big doors and 19 windows, and outfitted with ceiling fans and outlets. You can get a good look at the greenhouse in this video below showing the delivery. You can see it comes fully assembled. 

 

 

Before continuing with my greenhouse hacks and tips, I have an announcement. Because I heard from many gardeners that they regret missing the window to enroll in my Master Seed Starting course or they were hesitant to commit to the enrollment tuition, I am now offering a one-time seed starting webinar on Wednesday, February 28, at noon Eastern.

The webinar is titled “Fundamentals of Seed Starting Master Class – 10 Keys for Success,” and the cost is just $30. Just for those people who sign up for the webinar, if they decide they want to join Master Seed Starting, we will open up enrollment for a couple of days.

Fundamentals of Seed Starting Master Class will be recorded so those who registered but couldn’t attend live can view it on demand for a short period afterward. 

Up next is the relaunch of Organic Vegetable Gardening. That will be open for enrollment in mid-March, so stay tuned for details.

Check Local Restrictions

Check the local ordinances, zoning laws and homeowners association covenants and restrictions before ordering and siting a greenhouse. If you don’t, you could run into fines, long delays and unexpected costs.

The greenhouse I have comes fully assembled, so I had a concrete slab poured in anticipation of its arrival. I looked for a location that was flat and level and where the greenhouse would get the best sunlight, considering the tree canopy. I didn’t consider how far back from the property line a greenhouse was required to be. 

Hoping to avoid any snags, I sent in a permit application. Weeks went by without me hearing anything, and then one Friday I heard from the concrete company that they would be coming that following Monday to pour the pad. I tried to delay, but the concrete company said they did not know when they could get me back on their schedule because concrete is in short supply.

Because I needed the greenhouse in time for seed starting so I could raise seedlings to sell, I had a sense of urgency. I couldn’t push off the concrete company, so I had them come and pour the slab and hoped for the best. Just two days later, the response to my application came. A greenhouse was allowed, as long as it was set a minimum of 50 feet back from the property line. I went and measured, and it was only 20 feet back. Now I had a big issue.

 

Greenhouse slab

The slab was poured by the time I heard back that the location was too close to the property line. I needed to request a zoning variance to use the slab for my greenhouse.

 

I had to apply for a zoning variance. My city does not like to approve variances unless the applicant can prove hardship, which is a subjective case to present to convince a zoning board. I worked 10 months to build my case, including taking overhead drone shots to demonstrate that the greenhouse was really in the only place it could go. I have five acres, so naturally, the zoning board wanted to know why it couldn’t go elsewhere, where it would meet the setbacks. 

Peter Langham, a landscape architect and good friend of mine, jumped in to help me. He was a godsend because he provided his expert drawings and advice and helped me rehearse my spiel to the board.

Long story short, the zoning variance was unanimously approved. The takeaway from this is that if you are considering a greenhouse — especially if you live in an HOA or a city with restrictive zoning guidelines — make sure you are cleared for takeoff before installing anything. You don’t want to invest your time and energy and have your heart broken. 

Anticipate every possible question that can come up from the zoning board or HOA so you can have a rock-solid response that is irrefutable. 

 

Joe Lamp'l and greenhouse

Once a greenhouse is put in place, it is a chore to move it, and if you had a concrete slab poured already, that adds another complication.

 

Choosing a Greenhouse

I’ve been living at my current property for 12 years. I long wanted a greenhouse to complement my garden, but it took me time to act for a few reasons. Aesthetics was a big driver. Because my property often appears in my television and YouTube videos, I wanted a greenhouse that would tie in nicely with my house and garden. Some greenhouse styles and designs do that better than others. I felt like the one I wanted was out there but I just hadn’t found it yet.

Then one day I saw a video of Jill McSheehy of “The Beginner’s Garden Podcast” with her greenhouse, and I said, “That’s the one I’ve been looking for.” I got in touch with Jill and found out who makes that greenhouse — Yoderbilt. 

I spoke directly with the company’s founders and owners, Travis and Angela Yoder, on Zoom. I thought I wanted a 12-foot-by-24-foot greenhouse, but Travis talked me out of it. He told me I wanted something bigger, and the biggest Yoderbilt could deliver between Arkansas and Georgia is a 12-foot-by-32-foot greenhouse. He was right. I would have regretted the smaller greenhouse.

Master Gardener and hobby greenhouse owner Sheri George, mentioned in my interview with her that a greenhouse owner has never said “I wish I had a smaller greenhouse.” All greenhouse owners, no matter how big their greenhouses, want a bigger greenhouse.

My 12-foot-by-32-foot greenhouse looks big when it’s empty, but I quickly filled it up to the point that I had no room left for even one more seed starting tray. I was still wishing for a larger greenhouse, but at some point, you have to draw the line. And even if I really want to trade up, I can’t away, considering the Department of Transportation requirements for transporting an assembly greenhouse. 

My greenhouse is wood-based, with a wood floor and sides halfway up, and polycarbonate windows and top. It’s beautiful and blends in nicely with the aesthetics of the GardenFarm. But quality is just as important as the look, and when I did my research and read the reviews, I found Yoderbilt owners to be over-the-top happy with their decisions. 

 

Greenhouse

I needed a greenhouse that was both functional and aesthetically pleasing. I found it with Yoderbilt.

 

Greenhouse Options and Upgrades

Yoderbilt greenhouses also come with options on top of the many features included in the base model. I added on tables and benches for seed trays and pots, so everything was ready to go when it got here, and I didn’t have to think about where everything would go if it was in a greenhouse. If you’re handy you could build these yourselves, but maybe that’s not in your skillset.

Not included in the base model is an electrical package. If you don’t get the electrical package and still want to be able to plug in things like germination mats, fans and heaters, you will need to run an extension cord — which is not recommended practice — or hire an electrician to wire the greenhouse once it’s delivered. I chose the electrical package from Yoderbilt because I trusted that the company builds these greenhouses every day and knows what it’s doing.

I also opted for ceiling fans in the greenhouse to improve airflow. For the same reason, I also opted for extra windows. The base model does include windows, but not as many as I would like to ensure the health of the plants inside. Now I have great airflow from the front to back and side to side, which makes a world of difference.

You pay extra for these add-ons, but consider that a quality greenhouse will probably last you a lifetime. You don’t want to regret skipping the options, and it can end up costing even more to rig the greenhouse after the fact. 

A year later, I am so happy that I added electrical, extra windows, ceiling fans and the tables and benches. I also intended to run a water line to the greenhouse and had a stub included in the concrete slab so it is ready for plumbing. However, when I got a quote to tap into the main water source and run a line under the driveway to the greenhouse, it came out to $5,000. No way was I going to spend $5,000 when I could just run a hose in there or carry in watering cans. I would enjoy having water in the greenhouse at the flip of a valve, but I don’t mind doing what I do now.

Because the greenhouse is made with wood that is pressure-treated and rarely gets wet, I don’t worry about sealing or staining it. It will last, as long as I am responsible when applying water to the plants in the greenhouse.

 

Greenhouse with tables and benches

I opted for the electrical package as well as tables and benches that are the perfect fit.

 

Winter in a Greenhouse

Once the greenhouse was in place and installed, it was just me in the greenhouse. Standing there alone, I had to pinch myself to be sure I wasn’t dreaming. I just couldn’t believe it finally happened.

Upon becoming a greenhouse owner after thinking about it for so long, it’s like being thrown into the pit. There is a lot of knowledge to absorb, and that can feel like drinking out of a firehouse. You can do your research and join several Facebook groups about owning a hobby greenhouse, but nothing compares to hands-on experience. Being there for the ebbs and flows of the greenhouse over the course of four seasons was the greatest way to learn. 

Because my greenhouse was delivered at the end of December, the first season I experienced was winter. I learned that overnight, the temperature inside a greenhouse is the same as the temperature outside. Even on a cold day, a greenhouse gets warm or even hot inside, but then after the sun goes down, that warmth dissipates. 

I learned that to keep a greenhouse warm overnight in winter, supplemental heat and/or insulation would be required. Some greenhouses are all poly so they really can’t be insulated, but my Yoderbilt greenhouse has wood walls and had some gaps I could fill with insulation. The space between the skids that the greenhouse frame is built on and the concrete pad needed skirting to keep the warm air in overnight. I added insulating boards along the bottom, and that makes a big difference. For the air coming up from the wooden floor, I added 2-foot-square rubber puzzle-piece mats, and around the base of the walls, which are shiplap, I used eight foam boards cut to size.

 

Insulation boards help to keep warmth inside the greenhouse overnight.

Insulation boards help to keep warmth inside the greenhouse overnight.

 

The insulation kept the greenhouse 7 degrees warmer overnight. That’s not much, and that’s because it’s just a fact of life that greenhouses will always have air gaps where warm air can escape and cool air can get in. So this is where supplemental heat comes in.

If you intend to overwinter non-hardy plants in your greenhouse, you’ll need heaters. They could be electric, propane, kerosene, etc.

I use two electric oil-filled radiator heaters in my 32-foot greenhouse. These cost between $50 and $100, have three settings — low, medium and high — and they work well. I also use a Palma greenhouse heater, which is very popular among greenhouse owners. It has a thermostat, so it only turns on when the temperature in the greenhouse falls below 50°F.

 

Palma greenhouse heater

My Palma greenhouse heater has a thermostat, so it only turns on when the temperature in the greenhouse falls below 50°F.

 

Because I like redundancy, I also have propane heaters. They will ensure I can heat the greenhouse even if the power goes out. They use the same tanks used with a propane grill. I haven’t had to use the propane heaters yet, but I feel much better having these.

When I got my private pilot’s license, I learned that pilots always have redundancies. I take the same approach to my greenhouse. If another arctic blast comes to Georgia, I know that I can in place what I need to ensure my plants’ survival.

I also use a greenhouse temperature sensor that will send a push alert to my phone if the greenhouse falls below a set temperature. I use both a Govee and a SensorPush — because redundancy. In addition to alerts, they also track historical data such as highs and lows, and you can download it into a spreadsheet.

 

propane heater

I have two propane heaters as a backup in case the power goes out or there is an arctic blast.

 

How to Keep a Greenhouse From Overheating

In addition to setting alerts for lows, I also set alerts for highs. If a greenhouse gets overly hot, it can fry plants. I got one such alert when the temperature reached 103° one day while I was out. Thankfully, my daughter lives close by and she was able to stop by and open the windows and door.

When mounting your temperature sensor, placement is important. I erroneously mounted a sensor 9 feet up, and the high point in the greenhouse is 12 feet. Because hot air rises, this was higher than the sensor should have been. The sensor is more useful at the height that the plants sit, because that’s the temperature that I really need to know. The placement made a 15° difference in the temperature reading.

 

A ventilation fans moves hot air out of the greenhouse

A ventilation fan moves hot air out of the greenhouse.

 

Before leaving the subject of heat, I want to share what my friend Peter Langham told me: His greenhouse once got so hot that his plastic seed trays melted.

Now I take care to store plastic materials on the side of the greenhouse that gets the least UV exposure.

On a blazing hot day, a greenhouse will heat up even hotter — and your plants will not be happy in an oven. This is why ventilation is so important. There are many ways to let out the heat: open the windows, use thermostatically controlled bevels that activate at a certain temperature, turn on the ceiling fans, and use the exhaust fan on the backside of the greenhouse to pull air through and out.

 

These windows right near the ridge line of the greenhouse pop open to let out heat.

 

Another big one is shade cloth. Some people put these inside their greenhouse, but I secured it over the top. Other greenhouse owners recommended Aluminet shade cloth, which is an aluminum fabric weave. It knocked down the temperature by 15-20°. I put it on after the peak growing season in April and kept it on until I was ready to move my seeds in for seed starting in January.

 

Shadecloth over a greenhouse

In summer, a shade cloth can keep a greenhouse from overheating.

 

De-bug Plants Before Bringing Them in Your Greenhouse

Spray down plants with a stiff stream of water to get off the aphids and anything else that may be lurking on your plants. Once you bring pests inside the greenhouse, it only gets worse. They will thrive in that environment. I made this mistake and had to take my plants back outside to do what I should have done in the first place.

 

Aphids

Accidentally bring just a few aphids into a greenhouse and soon they will multiply exponentially.

 

Overwintering Dormant Plants

Because the greenhouse is so much warmer in the daytime than the temperature outside, plants that are brought in there may never go dormant or may come out of dormancy. I am going through this with some bare-root roses that I potted up in the greenhouse. They leafed out and went to flower, which means I can’t plant them outside now in the middle of winter.

Greenhouses and Cats

I have a couple of cats and a dog that love to hang out with me in the garden. One, Larrie the cat, really loves the greenhouse. In fact, I thought about installing a cat door on the greenhouse. However, fellow greenhouse owners warned me off. A cat door can also be a door for raccoons and other critters that would love to be in a warm greenhouse in winter. 

My greenhouse is also where I keep bags of soil, and that’s like the Cadillac of litter boxes. Cats also enjoy nibbling on the leaves of tender seedlings, to the point of pulling seedlings out of their pots. 

 

Seedlings in greenhouse

Larrie enjoys spending time in the greenhouse with me, but it’s a bad idea to let her come and go unsupervised.

 

Organizing a Greenhouse

I called Tobi, my farm manager, the other day and asked her for her takeaways from a year with a greenhouse. She mentioned many of the things I had thought of and also pointed out that I tend to move things around all the time, and then she can’t find things when she needs them. She suggested an organized, dedicated spot in the greenhouse where equipment and materials live. This includes big items, like a broom, down to the small things, like plant tags and scissors. Tobi had a great idea, so we will add a dedicated space in the greenhouse for those miscellaneous items.

 

Seedlings in greenhouse

A dedicated space for tools and materials is on my list of things to add to the greenhouse in 2024.

 

DIF

Because I sell seedlings, I need them to look as good as they possibly can in April. However, last year they looked picture-perfect in March and were still growing taller. The plants weren’t getting thin and spindly, but they were looking like trees. The internodal sections between the branching were not compact like they should be.

I theorized this is because I had so many seedlings bunched together and that they were competing for light. However, I learned this was not the case when I spoke to Dr. Charles Bethke, a previous podcast guest and the director of research development for PittMoss. Charles explains this is caused by DIF — the difference between the day and night temperature. 

“If the night temperature is cold and the day temperature is high, you have a high DIF,” Charles says. “… That difference between night and day then stimulates the plant to do hormonal things. And among the hormonal things, it recognizes the high temperature and it releases a lot more auxins and gibberellins.” After a cool night, the gibberellins become more active in the plant the next day.

“It is wise to reduce that DIF by having warmer nights and cooler days,” Charles says. By adding heat at night starting when a plant’s first true leaves are fully expanded, you’ll have a much better plant. And reducing the day temperature for a couple of hours in the morning, starting at or before daylight, will hamper “hormonal translocation” — shutting down the movement of hormones from the roots to the shoots. 

Plants will grow huskier, stockier and thicker in these conditions. It is an alternative to applying hormones to influence growth. Using DIF is why greenhouses can supply Easter lilies that are the perfect height, Charles points out.

He noted a study in Japan that involved watering tomato plants every morning at 9 o’clock with cool water. The study found that the plants had the same response. And it worked the same with other crops as well.

Greenhouse owners can cool a greenhouse by opening the vents at daylight, letting the temperature fall as low as the 40s or 35°. After there has been enough daylight, the hormones will start moving freely again.

You can do either or, or you can both run the greenhouse warm at night and also cool it in the morning to achieve stocky growth.

 

Tomato seedlings displaying DIF

The difference between the nighttime and daytime temperature influences how stocky plants will grow.

 

If you haven’t listened to my greenhouse hacks and tips, you can do so now by scrolling to the top of the page and clicking the Play icon in the green bar under the page title. 

Do you have greenhouse hacks and tips to share? Let us know in the comments below.

Links & Resources

Some product links in this guide are affiliate links. See full disclosure below. 

Episode 049: When Good Bugs Eat Bad Bugs: The Business of Beneficial Insects

Episode 093: Hobby Greenhouse Considerations: What to Know Before You Buy (and After You Do)

Episode 259: Getting to Know PittMoss, a Peat-free Growing Medium Alternative, with Dr. Charles Bethke  

Episode 295: Looking Back on 2022’s Garden Lessons

Episode 345: The Lean Micro Farm: Raise Crops with Maximum Efficiency

Episode 350: What to Know About Buying and Owning a Hobby Greenhouse

 joegardener Online Gardening Academy™: Popular courses on gardening fundamentals; managing pests, diseases & weeds; seed starting and more.

joegardener Online Gardening Academy Organic Vegetable Gardening: My new premium online course. The course is designed to be a comprehensive guide to starting, growing, nurturing and harvesting your favorite vegetables, no matter what you love to eat, no matter where you live, no matter your level of gardening experience.

joegardener Online Gardening Academy Master Seed Starting: Everything you need to know to start your own plants from seed — indoors and out. 

joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.

joegardener Online Gardening Academy Growing Epic Tomatoes: Learn how to grow epic tomatoes with Joe Lamp’l and Craig LeHoullier. 

joegardener Online Gardening Academy Master Pests, Diseases & Weeds: Learn the proactive steps to take to manage pests, diseases and weeds for a more successful garden with a lot less frustration. Just $47 for lifetime access!

joegardener Online Gardening Academy Perfect Soil Recipe Master Class: Learn how to create the perfect soil environment for thriving plants.

Earthbound Expeditions: Discover South Africa with Joe Lamp’l

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joegardenerTV YouTube: Seed Starting in the New Greenhouse | Getting Warmed Up

Growing a Greener World®  

GGWTV YouTube

joegardener Amazon shop

USDA Zone Finder

Electric oil-filled radiator heaters

SensorPush greenhouse temperature sensor

Govee greenhouse temperature sensor

Aluminet shade cloth

Propane heaters

Palma greenhouse heater

Proven Winners ColorChoice – Our podcast episode sponsor and Brand Partner of joegardener.com 

Territorial Seed Company – Our podcast episode sponsor and Brand Partner of joegardener.com 

Greenhouse Megastore – Our podcast episode sponsor and Brand Partner of joegardener.com – Enter code JG10 for 10% off your order

Disclosure: Some product links in this guide are affiliate links, which means we get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us, and compensation is not an influencing factor on their inclusion here. The selection of all items featured in this post and podcast was based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Corona Tools, Milorganite, Soil3, Greenhouse Megastore, Territorial Seed Company, Earth’s Ally, Proven Winners ColorChoice and Dramm. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship. 

About Joe Lamp'l

Joe Lamp’l is the creator and “joe” behind joe gardener®. His lifetime passion and devotion to all things horticulture has led him to a long-time career as one of the country’s most recognized and trusted personalities in organic gardening and sustainability. That is most evident in his role as host and creator of Emmy Award-winning Growing a Greener World®, a national green-living lifestyle series on PBS currently broadcasting in its tenth season. When he’s not working in his large, raised bed vegetable garden, he’s likely planting or digging something up, or spending time with his family on their organic farm just north of Atlanta, GA.

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