Is There a Greenhouse in Your Future?
March 20, 2017
This is the time of year when we think, “If we only had a greenhouse, we could grow…” (fill in the blank). We plantaholics whip ourselves into a frenzy and soon have seedlings perched in every window and on every flat surface in the house, so greenhouse envy is at its highest.
If you are planning a greenhouse project, here are ten tips to consider when choosing the perfect greenhouse structure for you:
- Purpose: What do you plan to do with your greenhouse? Use it as a season extender or for year round growing? Will you grow plants in the ground or in containers?
- Site: Will it be attached to your home or free-standing? Is the area level? Does it get enough sun? Are there trees that should be removed first?
- Style: Hoop houses and high tunnels are made from plastic or metal pipes bent into a round or gothic arch shape and covered with UV stabilized plastic. Traditional looking greenhouses are framed in wood or aluminum and glazed with polycarbonate, acrylic, or glass.
- Size: Everyone says to get the largest greenhouse you can afford because you will soon fill it and wish it were bigger, but it is more practical to plan the amount of usable space different sized houses will give. Biggest isn’t always best.
- Skill: Can you realistically build a kit or will you need to hire a carpenter?
- Foundation: Glass greenhouses need sturdy masonry foundations. Lightweight plastic covered greenhouses can be built with wooden bases and most hoop houses are attached to metal pipes driven into the ground. Temporary structures need to be anchored to the ground with stakes.
- Heat: Greenhouses heat up rapidly on a sunny day and cool off fast when the sun sets. Double walls - whether glass, polycarbonate, acrylic, or two layers of plastic sheeting with air blown in between them - will help to moderate the highs and lows. If you plan to grow year round you may need supplemental heat. Even if you are just raising seedlings in the spring, a portable heater may be necessary to see you through a cold snap.
- Ventilation: Doors, windows, vents, and roll-up sides all help to get fresh air into the greenhouse while exhausting hot, stale air. Tender seedlings fry fast on a sunny day! Thermostatically controlled fans or solar-powered vent openers will help regulate temperatures when you are not there. Shade cloth or nearby deciduous trees can help block the sun in summer.
- If you know anyone who has a greenhouse similar to the style you’re considering, ask if you can visit. Find out what they like and dislike about theirs and what changes they would make.
- Before starting any building project be sure to check your local building codes and zoning rules and get the necessary permits.
We now have a two-story glass greenhouse attached to the house that is not only used for plants but also gives us a lot of heat on a sunny winter’s day. Deciduous trees shade it in the summer.
Who needs a Caribbean vacation when you can grow tropical plants inside when there is snow outside.
When we decided to sell some of our excess seedlings to support our plant habit we built a hoop house to use as a sales area.
That wasn’t enough space though so we have some temporary greenhouses we throw together in the spring to house tomato plants, customer’s orders, and the plants we have chosen to keep for ourselves. Everything grows great in these inexpensive houses! For a few weeks each spring our yard looks like the circus has come to town but it is worth it for the healthy plants we are able to raise for ourselves and our customers.
Later we became the owners of a frame for a portable garage when friends were moving and just wanted it taken down.
Covered with greenhouse plastic it makes an ideal greenhouse for early tomatoes or for growing greens over the winter. With a few strong friends it can be moved to a fresh location each year. We kept the garage’s ends which have handy zippered doors!
About This Blog
Get inspired by Robin Sweetser’s backyard gardening tips and tricks. Robin has been a contributor to The Old Farmer’s Almanac and the All-Seasons Garden Guide for many years. She and her partner Tom have a small greenhouse business and also sell plants, cut flowers, and vegetables at their local Farmer’s Market.