I hope you enjoy this step-by-step tutorial on how to grow vegetables year-round in a greenhouse. It will give you an idea of the materials and steps we need to create our DIY greenhouse. This tutorial is meant for beginners with no prior horticulture knowledge necessary.
Table of Contents
- What is a Greenhouse?
- What Do You Need To Start?
- Step 1: Preparing the Greenhouse Frame.
- Step 2: Preparing the Soil for Planting
- Step 3: Planting Seeds/Seedlings
- Organize Your Seeds
- Water Plants as Necessary
- Irrigation System Ideas
- Step 4: Best Light Conditions
- Step 5: Maintaining Ideal Temperature
- Step 6: Feeding Your Plants
- Step 7: Removing Unwanted Plants and Root Systems
- Step 8: Preventing Pests from Harming Your Plants
- Spider mites
- Fungus gnats
- Luckily, there are several ways to prevent pests from ruining your plants.
- Step 9: Harvesting Your Crops
- Step 10: Cleanup After Growing Cycle
- Maintaining Your Greenhouse for Optimum Growing Conditions
- What Are the Best Types of Produce For a Greenhouse?
- Spinach and Leafy Greens
- How Does Climate Affect My Greenhouse?
What is a Greenhouse?
First off, let’s make sure you understand how a greenhouse works. Greenhouses are buildings designed primarily for growing plants out of season. These buildings also protect against harsh weather conditions.
Greenhouse structures typically consist of a framework covered with glass or plastic glazing, now often called “transparent insulation.”
If we don’t build one for a specific plant or crop, we can use greenhouses to grow vegetables and herbs year-round.
What Do You Need To Start?
- Empty greenhouse (or a building with sides that can be removed)
- PVC pipe or other frame material like wood
- Tables to work on
- Soil for planting and growing
- Seeds or seedlings of your choice
Step 1: Preparing the Greenhouse Frame.
Your greenhouse frame needs to be sturdy, which is why using a PVC frame might not be a good idea if you don’t know what you’re doing.
If you decide to use PVC, at least make sure there’s one end that can detach from the rest of the frame so you can easily move it or use it again another day without damaging all those expensive materials.
We must take the time to make our greenhouse frame sturdy, regardless of material.
- Construct the base from PVC, wood, concrete, or brick. The base must be able to support the weight of the greenhouse.
- Install support beams. The length will vary depending on your greenhouse size but should be around 3 feet high to prevent damage from strong wind gusts.
- Install 1×2 beams
- Install door. If you live in an area with lots of strong wind gusts, you will need to ensure this door is secure and can handle pressure.
- Install roof out of wood, metal, or plastic. It needs to be strong and handle the weather without risking damage to the structure. You want it to be able to support the weight of the greenhouse.
Step 2: Preparing the Soil for Planting
Using soil that has been tested is not recommended because it may be too rich for plants or vegetables that you want to grow yourself. Try starting with a base that isn’t mixed with anything yet.
This way, we know exactly what’s going into the ground where our food is growing.
If you’re starting with soil from another part of your home (like under your garden), make sure it doesn’t have any chemicals added like pesticides, herbicides, etc.
Plants can absorb these chemicals, and they may stay in the plant once we harvest and eat them. Also, keep in mind that water is approximately 80% of the weight of the Earth’s crust.
So, fertilizers and chemical nutrients from fertilizer can easily seep into the ground with too much rain.
- Get an old compost bin
- Put soil in the compost bin and mix thoroughly without adding any new material
- Let the mixture dry completely before planting.
Step 3: Planting Seeds/Seedlings
Once you have everything set up, including your greenhouse structure, soil, tables to work on, and seeds or seedlings that are properly germinated, we can now start planting our seeds and seedlings.
Organize Your Seeds
Before planting the seeds/seedlings, you want to grow, organize them first. If you’re doing more than one type of plant, I recommend that you use a separate table for each different one.
Place them in your greenhouse as you would in any other indoor planting environment. It is best to put each plant into its own pot.
When planting, make sure the soil you use is well mixed and doesn’t have any excess chemical nutrients or fertilizer in it yet.
Water Plants as Necessary
There is no need to flood the plant area. Believe it or not, excess water can cause many problems and diseases that spread quickly through too much humidity. Fungi and germs require water to spread and infect plants.
Too much water with poor drainage may also cause mold growth in the soil. Mold is not good for our health and affects the harvesting and consumption of crops. Mold can also make animals sick, so it’s important to keep that in mind.
A common plant disease resulting from water is root rot, which can kill a plant in a short time. Signs of root rot include wilting, weaker leaves, and lack of vigor.
The ideal amount of water is about an inch per week. As mentioned before, make sure you have a proper drainage system.
Also, try to water early in the day or late evening so that it will have a chance to dry before night.
Irrigation System Ideas
Make sure you have an effective way to keep plants moist all the time. Otherwise, they may dry out too quickly or not get enough water.
Planting containers are usually watered by either a drip irrigation system or through the bottom. If you have shallow roots, it’s best to water by the latter method.
Having a drip irrigation system in place is ideal since it can water both the top and bottom roots at optimal times. It’s also much more convenient.
When watering, look out for always-wilting leaves, mildew growing in the soil, and root rot.
Step 4: Best Light Conditions
In addition to water, our plants must have optimum light from a natural or artificial source.
Natural sunlight is preferred but not always available. To create a greenhouse environment for plants, we need to have the right combination of heat and humidity.
If necessary, you can also use grow lights at night since plants absorb more light energy than they do heat. So, it’s better to have a source of light that emits more energy, like grow lights.
For example, a common problem is that the lights are installed too close to the plants. If this happens, the leaves may burn and turn brown.
This happens because strong lights produce a strong electromagnetic field that can emit ionizing radiation. Ionizing radiation can zap the electrons in molecules like DNA, which is what damages plant stem cells. It’s not advisable to use black lights since they emit this type of radiation. The best lights are blue and red lights.
LED lights can work, but because they have a weaker magnetic field, it’s also possible to install them too close to plants.
Lighting may also be the reason why plants are growing slowly at first. They need time to acclimate to the new environment, which means they grow slower at first.
With time and patience, you will start seeing results as your plant grows.
Step 5: Maintaining Ideal Temperature
Before you install the greenhouse, make sure you have set everything up beforehand. Your greenhouse must provide an ideal temperature and light conditions for your plants to survive and grow.
You’ll want to monitor the temperature daily. Even if you have an automatic thermostat, it’s better to still monitor it yourself because certain conditions cannot be accounted for.
Aim to keep the temperature between 70 and 80 degrees Fahrenheit with an ideal temperature of about 75.
It’s also important to monitor and maintain your greenhouse humidity levels. We don’t want the humidity to fall too low. Low humidity may result in small leaves and dry conditions that make the plants more susceptible to drying out. In this case, we can consider adding a humidifier.
When the humidity is too high, we can experience problems with plants wilting and mildew.
We can control humidity by how good the ventilation is when there are fluctuations in air temperature. As we space out the plants adequately, ventilation improves.
Avoid leaving puddles of water on the ground, or it will increase humidity and breed mosquitos.
The greenhouse must also be well ventilated to prevent mold and decrease humidity. The air circulation also keeps the greenhouse cool during hot days and warm during cold nights.
Step 6: Feeding Your Plants
Use all-purpose plant fertilizer for your plants every 2-3 weeks. You can either spray it on or pour it around the base of your plants, making sure to avoid getting any on their leaves.
It will help them grow and look better over time with a little TLC.
Just remember that too much fertilizer is not good for anything. If someone in your home has asthma or other respiratory conditions, it could be worsened by chemicals in the air around them.
Step 7: Removing Unwanted Plants and Root Systems
It’s best to keep weeds out of the greenhouse since they will only take away important nutrients and water from your plants.
We must remove weeds quickly, so they don’t have the chance to break their roots and regrow in different spots.
Root systems can also become overcrowded, which will result in less-than-ideal plant growth. You can also remove unwanted plants by hand if it’s too difficult to find the main root system.
Herbicides also work well, but you should always spray in the late evening or early morning to avoid burning or frying your plants.
Transplanting is a great way to avoid overcrowding because it helps plants get more nutrients and light.
When transplanting, you have to be gentle with the plant to avoid damaging its roots. You’ll want to dig a hole that is about 2-3 times wider than the plant’s root system.
Hold the plant by its stem gently and carefully drop it into the hole, then cover the roots with soil.
Avoid transplant shock by making sure you have watered the plant well before and after moving it.
Step 8: Preventing Pests from Harming Your Plants
Now that we have our seeds planted, we must protect them until harvest. Just because your plants are in a greenhouse does not mean they are free from pests. Some typical greenhouse pests include:
These mites are tiny, and most come out at night. They will suck the juice right out of your plants until they are dry and withered.
These little white bugs love to feed on plant juices, too. The problem with them is that they spread extremely quickly. You’ll see these flying around in swarms if you don’t take care of any problems early on before they become an infestation.
You’re more likely to get this type of pest when using soil from outside your home because it could have eggs hidden in it without you knowing about it ahead of time. If you do find any caterpillars, make sure you pick them off one by one or use pesticides/insecticides to treat the greenhouse as a whole.
Aphids come in all different colors, and they love to suck the juice from plants, so they wilt and die. They can multiply very quickly, too, so it’s important to get them under control as soon as possible.
These pesky pests like to hide under leaves and then transfer over to other parts of the plant where you won’t see them until you start seeing yellowing leaves or a powdery-looking substance on your plant.
If you leave this untreated early on, it will spread like wildfire throughout your greenhouse.
These gnats are annoying as they love to feed on plant roots and also lay their eggs there. The result? Your plants will have stunted growth, yellow leaves, or die.
Luckily, there are several ways to prevent pests from ruining your plants.
- Cover the greenhouse with a fine mesh or plastic.
- Rinse the greenhouse before adding new soil to avoid bringing any unwanted pests from the soil you used before.
- Replace old soil periodically. Fresh new organic soil may help reduce the number of bugs living in it.
- Add floating row covers over plants when they are about 4 inches tall and leave them on until harvest to protect against small pests that hide under leaves.
- Use Neem oil for pest control, which comes from neem tree seeds. Only use 5ml per gallon of water mix together before spraying directly onto the plant. If you spray during the day, the sun will burn the leaves. Spray in the evening when it is cooler.
- Tobacco tea can also help prevent bugs in the greenhouse. Fill a clean trash bag with water and then add 1-2 handfuls of tobacco. Tie the bag shut, but not too tight. Steep for three days in the sun and then lightly spray on the leaves of your plants.
- If you find a bug, pick it off by hand or use pesticide to treat the greenhouse.
- Use pest traps. Get some that are either sticky or use natural chemicals to attract the pests away from your plants.
Step 9: Harvesting Your Crops
It’s hard to pick a perfect time to harvest your produce. So whenever you see a ripe fruit or vegetable, plan to harvest it.
If you grow a tomato, for example, you should see some changes in color from green to dark red or orange before it is time to harvest.
Before starting any crop, make sure you know how it will look once it is fully ripe. For example, a watermelon will turn a darker green before it ripens, and a tomato turns from green to red or orange.
Whenever you pick fruits and vegetables, make sure you do not damage other ones nearby that are still growing.
Step 10: Cleanup After Growing Cycle
It is time to start over again and create a new greenhouse to grow in the following year. Start by cleaning up all your old plant material, taking out old boards or whatever is in there that you will not be using.
Then clean the greenhouse before you start adding soil, fertilizer, and new plants for your next growing cycle. You should start your next cycle 4-6 weeks before the last frost of winter in your greenhouse.
Maintaining Your Greenhouse for Optimum Growing Conditions
Maintaining a greenhouse is fairly easy, so long as you properly construct it with enough ventilation and access points. If you need more space for growth, detach the side of the structure so it opens up more room inside if necessary.
It’s also good practice to remove any snow that might accumulate on top of your structure in wintertime. You don’t want it to melt into any unwanted puddles inside the greenhouse.
If you start to notice, any weeds taking over your crops, remove them as soon as possible. Anytime you see pests, spray the leaves and add fertilizer to keep the soil healthy.
You will want a greenhouse with plenty of natural light, so if it doesn’t get enough sunlight in your area, consider buying grow lights to help your plants along.
What Are the Best Types of Produce For a Greenhouse?
Most vegetables grow well inside a greenhouse, especially items like tomatoes, peppers, eggplant, and cucumbers. You can also plant root vegetables like carrots, beets, and turnips, as well as leafy greens like kale or Swiss chard.
The vegetables with the highest yield in a greenhouse environment include:
Spinach and Leafy Greens
When we grow Popeye’s favorite vegetable in our greenhouse, we get a clean leafy green that is free of debris and dirt. This crop can grow very quickly as well.
Because they are grown indoors, tomatoes don’t have to deal with the elements outside and can develop into a rich source of nutrition. These are the most common greenhouse vegetable to grow.
Beefsteak, cherry, grape, and tomatoes on the vine are all available to grow in your greenhouse.
Microgreens are an excellent source of vitamins and nutrients, which is why they make great kitchen additions to any home or restaurant. They are easy to grow in a greenhouse environment.
I love eating cucumbers in my salads. Luckily, they also produce a bountiful harvest in a greenhouse. These are also very profitable to grow for sale but don’t have a long shelf life after harvest.
There are several types of herbs we can grow in a greenhouse. One of my favorites is basil. Grow it in your greenhouse for use in all sorts of dishes, including Italian dishes, pesto, and even fresh summer salads.
I love mint in my iced tea, but it does get out of hand quickly. Luckily, growing mint in your greenhouse will keep it secured in one area with proper drainage.
Peppers are another delicacy that we may grow in a greenhouse with some effort. Grow bell, chili, and paprika peppers.
These are not the easiest crop on the list to grow, but if you master them, they can yield a good profit.
How Does Climate Affect My Greenhouse?
Temperature and humidity levels inside your greenhouse will be higher than outside as sunlight heats the air and plants release moisture.
Also, if you live in an area where it snows, take care not to build your greenhouse in a place where snow might accumulate and damage the structure.
Finally, if you live in an area with lots of wind and rainfall, make sure you add some roofing for your greenhouse to protect against any damage from strong gusts of wind or water.
If you live somewhere like Alaska, Canada, Greenland, or Sweden, where it gets cold in the winter but warmer during spring and summer, your greenhouse will be at its prime use to grow food during the warmer months.
For veggie growers in places like Australia or an area with hotter temperatures, make sure to protect your greenhouse from the elements.
Use it to keep your plants safe in the hot summer months.