Problems With Growing Cucumbers In A Greenhouse (And How To Fix Them)

Growing cucumbers in a greenhouse will not ensure a perfect crop. There can and will most likely be some problems unless you are actively keeping up with the plant as it grows. If you would like to successfully grow a cucumber plant in a greenhouse, you should keep up with pruning, properly space the plants, and ensure it is receiving enough water. 

What Are Some Common Problems Growing Cucumbers In A Greenhouse And How Do You Fix It?

Crowding Caused By Limited Space

Cucumbers are typically vining plants, so they require six to nine feet of space per plant. When you are growing cucumbers in a greenhouse, you might not have as much room compared to growing cucumbers in a garden outside. 

If your cucumbers are too crowded while growing in a greenhouse, there will be a few noticeable signs. The first sign of overcrowding is downy mildew or powdery mildew. This fungus will develop on the leaves due to poor air circulation caused by overcrowding. 

Another sign your cucumber plants might be too crowded would be smaller, yellow new growth. As the cucumber plant grows, the older leaves will shield the new growth from sunlight, causing the new growth to become stunted. 

Prune And Space Adequately

In order to ensure your cucumber plants grow healthy and strong in your greenhouse, you should keep up with pruning the leaves, and you should make sure to space the plants adequately when initially planting them. 

When you are planting cucumbers in a greenhouse, you should keep in mind that cucumbers will need at least three to four feet between each other. If each cucumber plant is put in its own container, you can easily move those containers as the plant grows. If you plant multiple plants in one container, make sure to measure where you are planting the seeds. 

Pruning is also important when it comes to ensuring your cucumber plants grow well in a greenhouse. As your plant gets larger, the new growth can start to crowd the old growth, causing poor air circulation. You should snap off little leaves and stems that grow in between the larger vines. You should also cut off dead or dying leaves and stems. 

Poor Watering Habits

When you are growing cucumbers in a greenhouse, you must know how much water the plant will need depending on the time of the year. If you are growing the vegetable during the winter, the plant will need less water than one grown during the summer. 

If a cucumber plant is not given enough water while being grown in a warehouse the leaves will wilt, turn brown and crunchy, and the plant will eventually die. 

If the cucumber plant is given too much water, the plant can become brown and soft, and the soil can begin to smell. That can be a sign of root rot. 

Water Often During The Summer Months

As your cucumber plant grows larger in the summer heat, it will need to be watered every day. You also need to water the plant every day because water is an important part of fruit production. If your cucumber plant is not getting enough water, the cucumbers produced can be small or even nonexistent. 

How much water should your plant get during the summer? As your plant starts producing cucumbers, it will need 1/4 gallon to 3/4 gallon of water per day. The amount of water will depend on the size of the plant. 

Water Infrequently During The Winter Months

Winter is typically a dormant period for most plants. The sun doesn’t shine as bright, and the air is dryer. However, greenhouses were designed to allow plant growth all year long. Keeping this information in mind, your cucumber plant will require less water when growing in the winter. 

 Cucumber plants should only need water once every 10-14 days. In that time, they should get about 1.5 inches of water. Another good way to know when your cucumber plant needs water is to stick your finger about one inch into the soil. If it is completely dry, you should water your plant. 

Disease For Days

If you are growing cucumber plants in a greenhouse, you probably have a smaller growing space than you would if you were growing the plants outside. This small space will make it easier for diseases to move from plant to plant. 

If your cucumber plant is suffering due to a fungus or disease, there are a few signs to check for. The first sign might be yellow or brown spots on the green leaves. The second sign might be brown or black leaves that are wilting and withering. Another sign of disease in a cucumber plant might be new growth that is hard, small, and withered. 

Preventative Treatment

In order to ensure the disease does not spread from plant to plant in your greenhouse, you should treat each cucumber plant with a preventative organic fungicide. 

It is important to use an organic product because whatever you spray on your plant will be absorbed by it. When you go to eat your plant, you will be eating that treatment. There are many vegetables approved fungicides out there that are completely safe to use on your cucumber plants. 

If you suspect one or more of your cucumber plants has a fungus or disease, you should immediately move that plant away from the others. This may be difficult if your are in a tiny greenhouse, but if you are growing the plants during the summer, you can briefly put them outside. You should not bring the cucumber plant back inside until you are sure the disease is completely eradicated. 

Do Cucumbers Grow Better In A Greenhouse?

Yes, your cucumber plant will grow better in a greenhouse because you can control the climate. Greenhouses usually have flaps that you can open or leave closed that will trap heat in the structure or allow breezes to flow through. Greenhouses will also protect your cucumber plant from an uncontrollable environment. 

When Should You Put Cucumbers In Your Greenhouse?

If your greenhouse is heated, you can plant your cucumber plant as early as March or April. Cucumbers are very susceptible to frost, so you should leave them in there until May. If your greenhouse is not heated, you should wait until April or May to plant cucumbers in your greenhouse. The first frost should pass before you use an unheated greenhouse. 

Can You Grow Cucumbers All Year Round In A Greenhouse?

If your greenhouse is heated, you can grow cucumbers all year long. You will also need to grow lights to supplement sunlight because the winter sun is weaker than the summer sun. If your greenhouse is not heated, you will not be able to grow cucumbers after November, when the frost has come. However, you will be able to extend the growing season. 

As you can see, there can be many problems when you attempt to grow a cucumber plant in a greenhouse. However, by keeping up with pruning, watering adequately, and giving each plant enough sunlight and space, a greenhouse will provide a strong and healthy plant. You will even be able to grow cucumber plants for a longer period of time, providing you with a healthy, homegrown vegetable! 

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