Can I Cover Tomato Plants with Plastic?

Tomatoes are delicious, healthy, and versatile. They can be eaten fresh, cooked, canned, or frozen, and they provide numerous nutrients, such as vitamins A, C, and K, lycopene, and potassium. However, tomatoes are also vulnerable to various pests, diseases, weather conditions, and environmental factors, which can affect their growth, yield, and quality. Therefore, many gardeners wonder whether they can cover their tomato plants with plastic to protect them and enhance their performance. Here is what you need to know.

The Benefits of Covering Tomato Plants with Plastic

Covering tomato plants with plastic can bring several advantages, such as:

Retaining moisture: By wrapping the tomato plants with plastic, you can reduce the amount of water that evaporates from the soil and leaves, thereby keeping the plants hydrated and healthy. Tomatoes need consistent and sufficient moisture to grow well and avoid diseases and disorders, such as blossom-end rot, cracking, and splitting.

Increasing temperatures: Plastic can act as a greenhouse, trapping sunlight and heat and raising the temperature inside the cover. This can help tomatoes grow faster and produce earlier or later, depending on your climate zone and planting schedule. Additionally, warmer temperatures can deter pests and accelerate the ripening process of the fruits.

Protecting from weather and pests: Plastic can shield the tomato plants from rain, wind, hail, frost, or drought, as well as from insects, birds, rodents, and other animals that may eat or damage them. By creating a barrier between the plants and the environment, you can reduce the risks of losses and setbacks and ensure a more predictable and successful harvest.

The Drawbacks of Covering Tomato Plants with Plastic

However, covering tomato plants with plastic can also have drawbacks, such as:

Overheating: If the plastic cover gets too hot, it can burn or wilt the leaves, stems, flowers, and fruits of the tomato plants. This can happen especially during summer days when the sun is intense and the air is humid. Therefore, you need to monitor the temperature and ventilation inside the cover and adjust it accordingly, either by lifting the plastic or cutting some holes in it. Additionally, you can use a shade cloth or a white plastic instead of a clear one, which can reflect more sunlight and reduce the heat.

Condensation: The plastic cover can also trap moisture inside it, creating a humid and wet environment that can foster fungal diseases, such as powdery mildew, gray mold, or early blight. To avoid this, you can remove the cover during the night or on cloudy days, or ventilate it regularly by lifting it or creating some openings. You can also use a drip irrigation system or a soaker hose instead of overhead watering, which can reduce the humidity and keep the leaves dry.

Restricted growth: Covering the tomato plants with plastic can limit their access to air, light, and nutrients, which are essential for their development and health. The plastic can also impair their root growth and cause them to become weaker and more susceptible to pests and diseases. Therefore, you need to make sure that the plastic cover is not too tight, and that the plants have enough space and soil to expand and thrive. You can also add some organic mulch around the plants, which can improve the soil quality, retain moisture, and reduce weeds.

The Types of Plastic Covers for Tomato Plants

There are several types of plastic covers that you can use for tomato plants, depending on your needs, budget, and preferences. Here are some examples:

Clear plastic sheets: These are the most common and affordable plastic covers, and they allow sunlight and warmth to penetrate through them, promoting photosynthesis and growth. They are ideal for starting tomato seeds, protecting seedlings from cold, and extending the tomato growing season. However, they can also cause overheating and condensation, as mentioned above.

Frost blankets: These are lightweight and breathable covers that can protect the tomato plants from frost, wind, and pests, without trapping too much moisture or heat. They are made of non-woven fabric, polypropylene, or other polyesters that allow air and water to pass through them, while blocking the cold or the insects. They are ideal for gardeners who live in cooler or unpredictable climates, and who want to reduce the risks of frost damage or pest attacks.

Row covers: These are longer and wider covers that can span over multiple tomato plants or garden beds. They are usually made of spunbond or woven polyester, which can trap more sunlight and heat than frost blankets, but also more humidity and pests. They can come in different thicknesses, colors, and shapes, and they can be opened or closed by zippers, ties, or clips. They are ideal for covering tomato plants that are growing in rows, and for creating a more uniform and protected growing environment.

High tunnels: These are large and semi-permanent structures that can cover an entire tomato garden or greenhouse. They are made of metal, wood, PVC, or other materials, and they can support plastic or shade covers, as well as irrigation and ventilation systems. They can provide a more reliable and intensive growing space for tomatoes, allowing them to grow larger, taste more flavorful, and yield more abundantly. However, they also require more space, time, and money to install and maintain, and they may not be suitable for small or mobile gardens.

The Precautions of Covering Tomato Plants with Plastic

Before covering your tomato plants with plastic, make sure to follow these precautions:

Choose the right type of plastic cover for your needs and climate, and make sure it fits well and does not suffocate or deform the tomato plants.

Leave some space between the plastic cover and the plants to allow air and moisture to circulate, or cut some holes or vents in the plastic to increase ventilation.

Monitor the temperature and humidity inside the cover regularly, and adjust it as needed by lifting, lowering, or removing the plastic, or by using shade cloth or fans to regulate the climate.

Water the tomato plants regularly and adequately, either by using a drip irrigation, a soaker hose, or a watering can, and avoid overhead watering that can create too much humidity and moisture.

Check the plants for signs of pests, diseases, or nutrient deficiencies, and treat them promptly by using organic or chemical controls, or by adjusting the pH, fertilizers, or soil composition.

Remove the plastic cover gradually as the tomato plants grow taller, stronger, and adapt to the outdoor conditions, and avoid exposing them suddenly or permanently to the harsh sunlight, wind, or cold.

Dispose of the plastic cover responsibly and sustainably, by recycling it or reusing it for other purposes, or by avoiding single-use or non-biodegradable plastics.

In conclusion, covering tomato plants with plastic can be a useful and effective way to protect them and enhance their growth, but it also has some risks and limitations that need to be mitigated and managed. By choosing the right type of plastic cover, monitoring the temperature and humidity, irrigating and fertilizing the plants properly, and taking care of their health, you can reap the benefits of plastic without compromising the quality and safety of your tomatoes. Happy gardening!