The perfect greenhouse: expert tips for selection and maintenance

Greenhouse: most common questions answered and professional tips

When is the ideal time to get a greenhouse?

Autumn is an excellent time for setting up a greenhouse [in Finnish]. Starting in autumn allows you to focus on construction. With the greenhouse ready by spring, you can start sowing as early as March and plant crops as soon as the ground thaws. Unlike in spring, the ground has settled in autumn and is no longer frozen.

Where should you set up your greenhouse?

You should choose a warm and sheltered location for your greenhouse. Make sure it’s in a sunny spot and will not get in the shadow of any trees or shrubs. This way the morning sun will warm the greenhouse early, while the evening sun will help it retain heat for the night. If the greenhouse is placed in a spot that gets full sun exposure, you can prevent excessive heat by shading. Place the greenhouse near your kitchen, as it’s easy to forget about using it if it’s placed in a far corner of the yard. Don’t forget to take local building regulations into consideration.

What type of greenhouse is suitable for a windy location?

In coastal and windy areas, a glass greenhouse typically performs best, as it withstands wind stress better than a polycarbonate model.

In windy conditions, a greenhouse needs to be securely anchored to the ground, as it has such a large surface area exposed to wind. It’s also important to ensure that the coverings are intact and that doors and vents stay closed to prevent wind damage during winter and stormy weather.

What size greenhouse should you consider?

A greenhouse can last for decades, so it’s important to carefully assess your space needs. Smaller models are typically used solely for cultivation, while larger models can also be used for leisure. The size of the greenhouse depends on the plants you want to grow, the choice of growing medium, and the desired yield. If you want space for working, leisure, or storage, the area needs to be even larger.

Opt for a greenhouse that is at least 2.5 meters wide. Width increases the volume of the greenhouse. Length can be added later, but a narrow greenhouse cannot be widened. A pathway width of 60 centimeters is suitable.

Should you choose glass or polycarbonate for your greenhouse?

Clear glass is a stylish, traditional covering material [in Finnish]. It is durable and cost-effective. A glass roof is ideal for summer, but polycarbonate handles snow loads better. A popular choice is to install glass walls with a polycarbonate roof.

Polycarbonate is impact-resistant and easy to install, and it is used especially in large greenhouses. It insulates heat, extending the growing season and reducing heating costs. Polycarbonate diffuses light rays, eliminating the need for shading.

Which type of greenhouse has the longest lifespan?

With an aluminum frame and tempered glass covering, a greenhouse’s lifespan is virtually unlimited, and it is contingent only on maintenance like tightening loose screws. Painted aluminum-framed greenhouses need hardly any maintenance and are durable, with no parts susceptible to rotting or rusting. A painted frame is easy to keep clean.

Do all greenhouse models risk snow load damage?

It’s a good idea to clear any snow from the roof of your greenhouse, as no greenhouse is designed to bear heavy loads. Lighter structures require more frequent care and snow removal during winter.

A ten-centimeter ice layer adds approximately one hundred kilograms per square meter. Ice forms beneath the snow, making it easy to overlook. If your greenhouse is at your summer cottage, for example, and visits during the winter are not feasible, support the greenhouse frame with a pole under the roof ridge. Additionally, place a sturdy and slippery cover on the roof to encourage snow to slide off.

To prevent the accumulation of snow, place the greenhouse in such a way that the ridge is in line with the prevailing wind direction.

Can you assemble a greenhouse yourself?

You can assemble a greenhouse using the provided instructions, given enough time. It typically takes a couple of days to set up. It’s advisable to set aside an entire weekend for the task. Installation services are available for those who don’t have the time or aren’t able to assemble the greenhouse themselves.

Begin by laying the foundation for the greenhouse [in Finnish]. If necessary, ensure proper drainage for the foundation. The foundation can be a metal base anchored to the ground or a block foundation. A block base is suitable, if you want fixed growing beds in your greenhouse. A well-constructed foundation makes the greenhouse look well-maintained. The floor can also be laid with concrete blocks [in Finnish] or bricks, which accumulate heat. A brick floor is also tidy and stays dry.

What are the common pitfalls when setting up a greenhouse?

Common issues arise from a hastily constructed foundation, which can cause the greenhouse to tilt and its glasses to break. A poorly made foundation is often the weakest link in the structure.

Soil types containing silt and fine sand are highly susceptible to frost heave and thus structural damage, and they require particularly careful foundation work.

Is automation worth considering?

Automation can aid in using the greenhouse and cultivating. All greenhouses should be equipped with ventilation hatches [in Finnish], but a hatch opener is worth considering. It opens the hatches automatically if the temperature rises too high while you’re away.

You can also equip the greenhouse with a non-electric watering system. A water barrel placed inside the greenhouse manages watering, allowing you to travel worry-free. It’s also worth considering lighting and electrification if you wish to extend the growing season with additional heating.

What should you grow in a greenhouse?

Tomatoes and cucumbers [in Finnish] are greenhouse staples. You will get the sweetest tomatoes if you allow them to ripen to a bright red color. Lettuce, dill [in Finnish] and parsley are worth growing in a greenhouse, where they get ready for harvest quickly. Heat-loving chilies [in Finnish], peppers and basil thrive in warmth. You can also pre-cultivate summer flowers in your greenhouse. It’s also worth trying something a bit more exotic, like growing grapes [in Finnish].

How to keep your greenhouse in top shape?

Keep you greenhouse tidy by removing dead and diseased plant parts. You should also replace the growing medium regularly. Grow bags can help keep your greenhouse tidy and they are easy to move around. It’s advisable to wash the greenhouse in spring and autumn [in Finnish] to prevent algae and other impurities from accumulating on the covering. During this time, clean the gutters and check the ventilation hatches and windows as well. Grease the doors and hinges at least once a year. From the start, it’s wise to choose a greenhouse for which spare parts and accessories are available.

Can a greenhouse withstand winter?

Make sure to close the ventilation hatches and doors securely in autumn to prevent storms from damaging the greenhouse. Whether you have a polycarbonate or glass greenhouse, you should clear snow loads off its roof to prevent glass from breaking or the frame from collapsing. If snow has frozen tightly on the covering, you can melt it away by heating the greenhouse. If the foundation is properly made, the glass will remain intact throughout the winter.

What determines the cost of a greenhouse?

There are significant differences between greenhouse manufacturers and models. Besides the area of the greenhouse, the price is influenced by the strength of the frame, covering material [in Finnish] and the height of the greenhouse. High-quality door opening mechanisms, locks, downpipes, and other accessories add to the cost. Generally, the more expensive the greenhouse, the higher quality and better equipped it usually is.

Expert: CEO Mikael Kivikangas, Kivikangas Oy