When Is The Best Time To Begin Greenhouse Gardening?

In the winter season, grow bulbs, cabbage, radishes, and salad crops like lettuce in your small greenhouse. Beginners should be prepared to sow hardy salads and oriental greens like mustard greens, pak choi, and winter varieties of lettuce towards the end of the month. Pinch out and plant in larger pots early sowings of sweet peas and onions. Top tip: Bring compost for sowing or potting.

To start growing plants in a greenhouse, note down your overall priorities and lay out what to plant and when so you can be ready to tackle the next growing season. A greenhouse allows you to start seeds at any time, extends the growing season, and offers opportunities for growing vegetables during the winter months. The structure also protects your plants from hungry insects.

Greenhouse growing is not just for commercial growers; it is possible to grow in a greenhouse year-round, but it will be easier for some and more challenging for others depending on the local climate. Heated greenhouses allow for maximum, year-round use, but are rarely used. Most seedlings can be safely grown in an unheated garden greenhouse when the temperature is between 10 degrees Celsius or 50 fahrenheit and 21 degrees Celsius or 70 fahrenheit.

A greenhouse allows you to sow seeds at almost any time of year, depending on the winter temperatures in your climate zone. Mid-spring is the best time to sow fast-growing tender plants such as courgettes, squashes, pumpkins, cucumbers, French beans, melons, and sweetcorn. In the northern region of the United States, it is not recommended to plant in a greenhouse until after Valentine’s Day due to low light.

In August/September, start planting your winter garden, as day length shortens from November through January, allowing plants to grow very quickly.

Do greenhouses get too hot in summer?

Greenhouses, whether made of glass or plastic, can become extremely hot during summer months. To provide warmth and protect plants from the heat, it’s crucial to keep them cool. Ventilation is a natural and effective way to keep the greenhouse cool, especially during spring and autumn when the sun is still strong. Proper ventilation promotes air circulation and helps control the temperature in the greenhouse.

When can I put plants in a plastic greenhouse?

In spring, mini greenhouses can be filled with young plants ready for transplanting into the garden. These plants, particularly salad crops, can be grown directly from seed. In summer, they can be used for protected crops like tomatoes, peppers, cucumbers, and aubergines, while the remaining space can be used for homegrown Mediterranean crops. In autumn, cuttings from fuchsias and geraniums can be taken to provide plant material for next year. Salad crops like lettuce can be planted in the mini greenhouse to ensure a steady supply during winter months, and vegetables like Spring cabbage can be grown on ready for planting.

Do I need to harden off seedlings before putting in greenhouse?

Hardening off is a crucial process for mature plants grown inside a greenhouse, as it involves slowly acclimating them to a new environment to prevent shock, damage, or even death. When plants are raised indoors in early spring and moved outside for planting, they must adapt to direct sun, cooler temperatures, lower humidity, increased air movement, winds, and pest and disease pressures, which are unpredictable and out of control.

Proper hardening off results in thicker cell walls and leaf structures, increased energy for root development, and reduced excess water, making the plant stronger, more rigid, and less susceptible to freeze damage. As plants grow slower, they create a firmer, less floppy plant that can handle the stresses of the outdoors. If not hardened off, wind, sun, or cold can lead to significant wilting, browning leaf edges, or even death.

Hardening off is a time-intensive process, ideally done over two weeks, but it is generally more sensitive than bringing home well-rooted, mature plants from a greenhouse and acclimating them to their new environment. It is essential to follow guidelines for hardening plants off when preparing for outdoor planting and to simplify the process when moving crops outside for sale or at home.

Can I start seedlings in an unheated greenhouse?

Seedlings can be placed in an unheated garden greenhouse when they are still small, such as in their seed starting trays or pots. They can be transplanted when they have just two sets of leaves upwards, usually 2-4 weeks old. The ideal temperature for starting seedlings is around 18 degrees Celsius or 65 degrees Fahrenheit, with a nighttime temperature of around 10 degrees Celsius or 50 degrees Fahrenheit. Too much temperature drop can hinder seedling development, and anything over 24 degrees Celsius or 75 degrees Fahrenheit is considered too warm.

Should a greenhouse be in the sun all day?

Greenhouses should be placed in areas with uninterrupted sun and protection from cold winds to promote plant growth. Wood is a popular material for glasshouses, with a natural metal or painted finish. It requires no upkeep and produces minimal shade. Wood is a traditional building material, suitable for some garden styles but requires periodic maintenance. Wooden frames are bulkier and can cast excessive shade. The height of the eaves at the eaves is crucial for light transmission and plant growth. A minimum of 1. 5m (5ft) tall eaves is recommended, with a maximum of 1. 8m (6ft) or more.

What not to grow in a greenhouse?

Greenhouses are ideal for gardeners as they provide controlled environments that extend growing seasons and protect plants from harsh weather. However, not all plants thrive in enclosed spaces. Some common mistakes to avoid include large trees and shrubs, which can outgrow containers and damage structures. Invasive plants, such as mint or certain ivy species, can quickly overtake other plants and become difficult to eradicate once established in a greenhouse.

To avoid these issues, it is recommended to reserve your greenhouse for compact or easily pruned plants. Additionally, plants with high temperature requirements, such as long-lived perennials, should be kept outside for easier control. By avoiding these common mistakes, you can save time, effort, and disappointment in your greenhouse gardening endeavors.

What temperature is too cold for a greenhouse?

To maintain optimal plant growth, keep your greenhouse temperature below 3C (37F). Tender plants like pelargoniums, half-hardy fuchsias, and citrus trees prefer a minimum of 7C (45F), and safest at 10C (50F). This temperature is ideal for young plants and plug plants. If you have a conservatory, use it to overwinter delicate plants. Position heaters carefully, placing them in an open, central spot away from water and angling the heater to prevent foliage desiccation by direct airflow above nearby plants.

What time of year should you build a greenhouse?

The optimal time to install a greenhouse is winter or autumn, as it is less time-consuming, economically profitable, and does not require planting anything. Cellular polycarbonate is the main material used for greenhouse production, allowing installation at any time of the year. However, the spring gardening season is often crowded with orders, leading to missed deadlines. Despite this, winter or autumn are the best seasons for greenhouse installation due to the favorable weather and lack of planting.

Alternatives to spring include installing in the summer, when temperatures are cooler and the site is not yet planted. Overall, the optimal season for greenhouse installation depends on factors such as weather, location, and the availability of cellular polycarbonate.

Can you grow in a greenhouse all year?

Greenhouses can be used year-round, even in cold weather, with a smart planting strategy. A fully insulated solar greenhouse design with climate control systems can grow almost any crops year-round. Greenhouses provide growers with the opportunity to harvest fresh fruits, vegetables, and herbs anytime of year. However, to grow the best produce, specific challenges in planning and care must be addressed, including heating and irrigation. To grow the best produce in a year-round greenhouse, it is essential to carefully manage all aspects of the greenhouse, including heating and irrigation.

When can I start using an unheated greenhouse?

It is recommended that the growing season commence in an unheated greenhouse during the late winter to early spring period, typically 4-6 weeks prior to the average date of the last spring frost. For example, if the last frost date is estimated to occur around May 1st, it would be advisable to commence utilisation of the greenhouse in mid to late March. During this period, the greenhouse provides an environment conducive to optimal growth.

When can I move my seedlings to the greenhouse?

Seedlings can be placed in an unheated garden greenhouse when they are still small, such as in their seed starting trays or pots. They can be transplanted when they have just two sets of leaves upwards, usually 2-4 weeks old. The ideal temperature for starting seedlings is around 18 degrees Celsius or 65 degrees Fahrenheit, with a nighttime temperature of around 10 degrees Celsius or 50 degrees Fahrenheit. Too much temperature drop can hinder seedling development, and anything over 24 degrees Celsius or 75 degrees Fahrenheit is considered too warm.