Greenhouse Effect:
Rain, Rain Go Away, Come Again Some Other Day
Gardening weather here is somewhat unpredictable, but generally on the cool side, dry in July, August, and September and more than wet the rest of the year.
Full on winter in Ocean Shores is really wet. If you follow the Ocean Shores Monthly Rainfall data put out by Walter Weed for the Coastal Interpretive Center, published in this paper, you’ll see the following monthly averages as:
- 8.70 inches – November
- 9.74 inches – December
- 9.96 inches – January
They record our yearly average at 58.02 inches. That’s to say nothing of the winds that usually accompany storms. Our winter sunlight averages range only about a third of the day, hovering around 8 hours. With so much rain, wind and so little sunlight, winter isn’t really the best time for gardening here, even in a greenhouse.
Greenhouse Effect
Greenhouses keep temperatures warmer inside than outside via the well known effect named for them: The Greenhouse Effect. The first Greenhouses were made from glass, although now they are made of other materials such as fiberglass, transparent or translucent polycarbonates, simple flexible plastic sheeting, or newer types of plastics designed specifically for greenhouses. Whatever material is used must be transparent or translucent to allow a significant portion of the light spectrum from the sun through it. In greenhouses, visible light in the red, yellow, and blue spectra need to pass through the material so that plants can use it for photosynthesis. (Note that most plants do NOT use green light but reflect it back, which is why most plant leaves look green.)
Some of the materials designed for greenhouses (like the Solar Gem’s fiberglass) are created to gather up and redistribute portions of the light spectrum especially needed by plants. Glass in a car or home, in contrast, lets in most of the visible light available.
When light passes through a window nothing happens to it until it strikes something. Then it is either absorbed or reflected back fully or partially by whatever it strikes. Often the frequency of light is changed as it strikes something. Any new reflected frequency that is not able to pass back through the window is converted to heat. Greenhouse gases such as carbon-dioxide, methane, or nitrous oxide do the same thing. So, the inside of the greenhouse heats up (as does the surface of the Earth from the greenhouse gases in the atmosphere.) The greenhouse effect can become extreme, such as in a car on a very sunny day. You know that from your own experience. Try touching a vinyl seat or steering wheel after leaving the car in the sun. Sunny day summer temperatures inside can reach 130o to 150o F or even higher due to the greenhouse effect. Greenhouse temperatures can burn and/or destroy plants which is why each of the greenhouses highlighted below has some kind of venting system.
So, what many North Beach gardeners do is build greenhouses where they can practice climate control. I would like to share with you some of the ready-made and home-made greenhouses of Ocean Shores.
READY-MADE GREENHOUSES
Here are some examples of ready-made greenhouses that anyone can purchase and modify to their own specifications.
Garden by the Sea (Solar Gem)
The Garden by the Sea greenhouse is a Solar Gem, many of which you can see throughout Ocean Shores. It is made in one piece from a fiberglass specifically designed to capture and distribute sunlight to the best advantage for yearlong plant growth.
It is also covered with a gelcoat to prevent fading. An automatic venting system controls the heat on overly sunny days. A small heater can be added if needed during the winter. All Solar Gems are installed by the company to survive our winter winds. In the early spring, we start veggies and flowers to get a jump on our short growing season. This year, we are experimenting with winter gardening projects to take fuller advantage of what the greenhouse can offer. Our 8×10 foot variety is the largest offered, of several sizes. You can purchase several plant bench-options as well. For more information on the Solar Gem, see: www.solargemgreenhouses.com
Jacqui Austin (Palram Hobby Greenhouse)
Build from a kit, Jacqui Austin’s greenhouse is tucked into an outside southwest facing corner of the house. Here it is protected from the wind but exposed to enough sun and heat that it sometimes needs a shade cloth. It has an automatic vent at the top for air circulation which is assisted by a small fan at the bottom.
Jacqui has personalized the greenhouse by building her own tables and benches, and adding grow lights for the shorter winter days. The 4 by 6 foot Palram Hobby Greenhouse is made from clear polycarbonate that blocks damaging UV light. With a rust resistant aluminum frame it was easy to install. Although she has used it to start seeds for her spectacular ourside garden, it currently houses her extensive collection of succulents. For more information Google Palram Greenhouses (www.palramapplications.com).
PJ Ford (Santa Barbara Greenhouse)
PJ Ford’s 4×10 foot greenhouse is built from a Santa Barbara Greenhouse kit. (sbgreenhouse.com) When she put it together about a year and a half ago, one of our Ocean Shores storms “walked” it across the yard.
It is now a sturdy plant home provided with water, air circulation, and shade cloths, tethered near a protecting fence so that it has no more tendencies to wander. When planning a greenhouse, one of the more important things for Ocean Shores residents to consider is the wind. Whether purchasing a kit, a completed greenhouse or building your own, make sure your final product will stay dry and secure.
Earlier in the year PJ started various vegetables and herbs for outdoor transplant, and grew some to maturity in the greenhouse. She also keeps a collection of succulents in part of the greenhouse. For the winter, PJ moved a number of more tender outside plants and a few house plants, into the greenhouse to join her succulents. So in contrast to Marlene’s “resting” greenhouse, PJ’s is protecting a full house of plants, expanding the number of species she can grow. Though not as warm as the spring or summer, inside temperatures on sunny days will rise enough that the ventilation system will be needed to keep from overheating plants.
HOME-BUILT GREENHOUSES:
Let us look at some home-built versions. Here are two contrasting greenhouses built by experienced gardeners. Notice how each, created by and for the gardener’s own purpose results in completely different types of plant friendly structures.
Kathy Sandefur
Kathy Sandefur and her husband built their greenhouse from recycled materials left from their decking project and from salvage companies such as offerup.com.
Note how David’s careful building skills have resulted in an actual house. Most of the windows open to allow for heat venting. Kathy grows tomatoes, cucumbers, hot peppers and zucchini, all summer and into the fall, giving her a long productive harvest as late as December. This fall she tried try some cool season veggies like lettuce, snow peas and basil, from seeds developed for greenhouses and not needing insect pollinators to produce fruits. An added benefit is that the greenhouse also serves as a sunroom from which to watch birds, listen to the rain and share the warmth with the plants as it gets colder outside.
Nevin Aspinwall
Nevin Aspenwall is known around these parts for his orchids – not the tropical kind, but those that are at home in a shady, cool climate.
He and his brother built his greenhouse back in January 2013, to house the dormant orchids he brought in a U-Haul all the way from St. Louis.
The wooden and translucent fiberglass greenhouse is built and functions entirely for the plants. As his orchids naturally grow in low light, shade cloths cover most of the structure. Parts of it are not tall enough for one to stand in. The structure includes an exhaust system controlled by a thermostat and a timed watering system. It includes separate beds, each with soil pH controlled for the particular species it will support. Raising orchids from seed is a complex process.
Nevin has also build a lab, in which he begins the orchid reproduction process in petri dishes and later transfers growing plants to the greenhouse.
Marlene Thomasson
Marlene’s greenhouse was built in 2018 by her husband, Ron, from tempered windows originally a part of the sunroom in their home, damaged by a winter storm. (Note that the winds are strong enough to challenge a permanent house as well as a greenhouse!)
Marlene’s greenhouse is glass from floor to ceiling, on three sides plus the roof. It is meticulously assembled with no chance of leaks or wind damage. A little more elaborate than some of the kits, her greenhouse includes boxed beds on the ground, two layers of shelving, and is plumbed and powered with a timed watering system and air circulation. Note the stained glass window Marlene added that, along with CD music, make it a pleasant place to work when garden chores get lengthily during the spring and summer.
Finishing up her second season in the greenhouse, Marlene grew peppers, tomatoes, herbs, lettuce, carrots and other salad vegetables this past year. The house is now cleaned, cleared out, and fully winterized for dormancy this winter.
Sabine Price – Storage Box Mini-Greenhouse
If you don’t have a greenhouse, you can still use the greenhouse effect to grow plants beyond the normal growing season. Sabine Price, a Master Gardener, does not have a greenhouse, but she has found ways to take advantage of how a greenhouse works. This past spring season she had some tomato plants that she kept in her car to warm them up and kept them thriving until it was time to plant them outside! (Dang, I wish I had gotten a picture of that!) Her tomatoes had such a nice start they outpaced mine by a lot!
She has since gotten more inventive and found a YouTube video that shows how to create a mini-greenhouse:
(https://www.youtube.com/watch?v=7IXn2t8GLh0&ab_channel=RootsandRefugeFarm )
Just get a clear or translucent plastic storage box, and a bag of garden soil or mushroom compost (sized to fit the storage box.) Place the soil, still in the bag, on the inside of the box lid that is placed on the ground; cut a hole in the bag, leaving the sides intact to hold the soil in, and plant directly into the bagged soil. Then place the box over the soil, to create the “greenhouse effect.” Watch to keep the mini-garden watered. You might also want to check it on warm sunny days to be sure it does not get too hot. If so, just leave the top off for a while to cool it down. Remember to replace the top at night.
Sabine has managed to grow some mesclun (a mix of salad greens) beets, radishes, kale, and spinach. Most of these did well throughout October, and she was able to harvest some of the leaves to add to salads. But into November the beets, radishes and some of the spinach had wilted. Even seasonal gardening in Ocean Shores offers challenges, so winter gardening is tricky too. But Sabine had enough success to give it another try. This system can also be used to get a head start on the spring season.
For questions, comments about this article or to share your gardening experiences, please contact Dauna at: dauna@gardenbytheseaoceanshores.org
This article was originally printed in The Ocean Observer (in multiple parts), November/December 2020 & January/February 2021
