By Jennifer Poindexter
Is a greenhouse the newest addition to your property?
If so, you might be scrambling to learn all the different ways you can use it. One way your greenhouse can be useful is to grow tomatoes.
There isn’t a ton of difference between growing tomatoes outdoors or in a greenhouse. If you’re interested in learning how to put your greenhouse to work in this area, you’re in the right place.
I’ll walk you through each step of the process. Here’s what you must know to produce gorgeous greenhouse tomatoes.
Growing Conditions for Tomatoes in a Greenhouse
Let’s begin with the obvious questions? Why should you grow tomatoes in a greenhouse instead of in a typical garden?
A greenhouse can be helpful to extend the grow season, and in my experience, tomatoes produce better inside a greenhouse. The heat, if vented properly, seems to help them thrive.
The greenhouse setting also is great for deterring impacts from the elements surrounding your tomato plants.
In periods of heavy rain, it can create ideal conditions for fungal diseases to harm your crops. A greenhouse can help stop these effects.
Now that you know why you might want to consider growing tomatoes in a greenhouse, let’s discuss how you create the ideal growing conditions.
Tomatoes can be grown in containers, planted in the ground, or planted in raised beds when growing in a greenhouse.
If growing tomatoes in a container, ensure it drains properly. You should also plant the tomatoes in amended, quality, well-draining soil.
Tomatoes need a minimum of eight hours of sunlight. If you’re growing tomatoes year-round, you might need to supplement with a grow light.
Keep in mind, grow lights require two hours to every one hour of natural sunlight. It’s a good idea to put your grow lights on a timer to make sure your plants are getting every hour of light they need to thrive.
The last thing you must consider when creating ideal growing conditions in your greenhouse is heat. If you’re growing tomatoes during colder portions of the year, the greenhouse can’t get lower than 60-degrees Fahrenheit at night and should hang around 70-degrees Fahrenheit during the day.
Be prepared to supplement heat as needed to give your tomatoes exactly what they need to thrive inside your greenhouse.
Now that you understand what your tomato plants need, let’s discuss how you can begin growing them.
How to Plant Tomatoes in a Greenhouse
When growing tomatoes within a greenhouse, it’s best to choose determinate or smaller varieties of the plant.
The reason being, if you plant indeterminate tomatoes, they could take over your entire growing area. Once you have the right variety picked out, it’s time to decide if you’ll transplant seedlings or grow your tomatoes from seed.
Don’t fret if you haven’t quite decided. I’m going to walk you through each method of planting. The easiest way to begin growing tomatoes is to transplant seedlings that you’ve purchased from a local nursery.
If you’re growing tomatoes in a bed, raised or in the ground, be sure there’s three feet of space between the rows and two feet of space between each plant.
Dig a hole deep enough to support the roots of the plant. Place the plant in the hole and fill in the hole. Press the soil around the base of the tomato plant to avoid any air reaching the roots of the plant.
You follow the same process if growing in a container. The biggest difference is you’ll want only one plant per container.
Also, ensure the container is large enough to support the plant in its mature state.
The next method for growing tomatoes is from seed. There are two different ways to go about this. The first is to start your seeds in grow trays.
Be sure to fill the grow trays with quality soil. Put two seeds in each cell of the grow tray. This is an insurance policy in case one of the seeds fails to germinate.
Once the seeds germinate, ensure they receive plenty of sunlight. Keep the soil moist by misting it with a spray bottle.
When the plants are approximately a half foot tall, it’s time to transplant them to their permanent location.
Use the same spacing mentioned above depending upon if your tomatoes will be grown in a bed or a container.
You can also direct sow tomato seeds. Plant the seeds approximately three inches below the surface of the soil and try to keep a foot of space between each seed.
Keep the soil moist while you’re waiting on germination to occur. Once the plants have sprouted, thin them to where there’s two feet of space between the plants in a bed.
If you planted multiple seeds in a container, for germination insurance, pick the strongest plant and remove the others.
It’s wise to use scissors to remove the unwanted seedlings. Snip the seedlings at the soil level to remove them. This avoids damaging the roots of the tomato plants you’re keeping.
These are a few ways you can begin growing tomato plants in your greenhouse. Pick the option which works best for you and begin your greenhouse gardening journey.
How to Care for Greenhouse Tomatoes
Caring for greenhouse tomatoes isn’t an overly complicated process. Tomatoes need water no matter where they’re growing.
Use the deep watering method when raising tomatoes in a greenhouse. You can apply more water fewer days of the week.
When you insert your finger into the soil, and it feels dry to the first knuckle, you know it’s time to add more water.
This method of watering helps to avoid overwatering while also encouraging deeper roots. You may need to water plants more frequently in a greenhouse than outdoors because they’re growing in less soil.
However, practicing this style of watering is still a great way to supply what your plants need while maintaining optimal health.
The next thing you should do is fertilize your tomatoes. The fertilizer should be high in phosphorus, calcium, nitrogen, and magnesium. Follow the instructions of your chosen fertilizer to be sure it’s applied correctly.
Once your tomato plants reach a foot in height, it’s time to begin staking them. You can use tomato cages or other methods of staking. The main thing is to provide support to ensure the stems don’t break.
Tomato plants do need to be pollinated. You can help them by shaking your plants, gently. You should also remove the bottom foliage of the plants. This helps lessen the amount of soil and water which will cling to them and can avoid disease.
When your plants begin fruiting, thin them to where there’s only five tomatoes per plant. This will reduce the load on them.
You should also spray your plants weekly with an insecticide and fungicide to prevent pests and diseases.
There are special things you’ll need to do if you’re growing tomatoes in your greenhouse during the summer.
The first is to monitor the humidity. It should be around 80% humidity inside your greenhouse. If you go above this, you’re creating an ideal space for fungal disease.
You should also vent your greenhouse during the summer. When it’s 80- and 90-degrees Fahrenheit outside, it’s going to be sweltering in your greenhouse.
This will cause your plants to become stressed. Be sure to provide air flow, so the heat has somewhere to go to avoid harming your plants.
By following these tips, when caring for your tomatoes, you should have an enjoyable growing experience.
Pests and Diseases Which Impact Greenhouse Tomatoes
Inside a greenhouse, the biggest threats to your tomatoes are fungal diseases. You can spray the plants with a fungicide, weekly, to head off any potential issues.
However, there are multiple pests you must remain aware of when growing greenhouse tomatoes. The main pests which could bother your tomatoes are aphids, flea beetles, whiteflies, and cutworms.
Yet, if you spray your tomatoes with an insecticidal soap and place diatomaceous earth around the base of your tomato plants, you should be able to treat and deter any potential threats.
Hopefully, your tomatoes will grow to become strong and healthy by staying aware of what could find your greenhouse and bring harm to your plants.
How to Harvest Greenhouse Tomatoes
Harvesting greenhouse tomatoes isn’t different from when you grow them anywhere else. When the tomatoes begin turning their assigned color, pick them.
Don’t allow your tomatoes to become too brightly colored because you risk them becoming overripe. This will only attract pests to your plants.
Once the tomatoes are picked, place them on your counter (out of direct sunlight) or in a brown paper sack to finish ripening.
You can enjoy them as-is or preserve them via freezing, dehydrating, or canning. Tomatoes can also be stored in your refrigerator.
However, be sure to set them out on the counter, for a few hours, before use to allow the juices to begin flowing again.
Growing tomatoes in a greenhouse could be a wonderful experience. It could allow you to have delicious, homegrown tomatoes year-round.
If you love their fresh taste and the experience of gardening, consider using your greenhouse for this purpose. It could become your new favorite method of growing tomatoes.
More About Greenhouse Tomatoes
https://www.oregon.gov/deq/FilterDocs/PEF-Tomatoes-ExecutiveSummary.pdf
https://edis.ifas.ufl.edu/cv266
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