A greenhouse can give you a whole new dimension in gardening. Here you can start growing earlier in the spring, extend the season well into the fall and grow plants that would otherwise not thrive in our climate. With a little planning and regular care, both beginners and experienced hobby gardeners can get great pleasure from a greenhouse.
Why get a greenhouse?
The greenhouse creates a warm and protected environment where sprouts and plants thrive better than outside in the garden. You can sow earlier, extend the harvest and grow exotic plants, vegetables, herbs and fruit that would otherwise have difficult conditions in Norway. For many, the greenhouse becomes a social space – a small green sanctuary in everyday life.
Planning and location
A good start is all about the right location:
• Choose an area with plenty of sunlight throughout the day, preferably facing south or southwest.
• Make sure it is sheltered from strong winds – a sheltered corner in the garden provides both security and better temperature control.
• Avoid placing directly under large trees – branches can break and damage the glass, and leaves can shade the light.
Base and foundation
A solid base provides stability and easier maintenance:
- Directly on the ground: Natural and simple, but more demanding to keep clean.
- Cast floor: Makes cleaning easier and reduces moisture.
- Plinth or foundation: Raise the greenhouse approx. 10–15 cm for better stability, less moisture and a more aesthetic appearance.
Rules you should know
In many municipalities you can build smaller greenhouses without a building application, but there are limits on size and distance to the property line and road. Check local zoning plans and inform your neighbors before you start.
When should you sow?
Most people start in April–May, depending on where in the country they live. Always wait until the danger of night frost is over. If you are going to use the greenhouse before March, you will need extra heat and preferably additional lighting. On hot summer days, you will need to ventilate to avoid overheating – an automatic window opener can be a good investment.
For an early start, you can pre-cultivate: grow summer flowers, herbs and vegetables that will later be moved outside when the temperature allows.
Good soil and proper fertilization
At least as important as location is the quality of the soil. Use nutrient-rich potting soil and add organic fertilizer to give the plants a good start. Top up with new soil as needed throughout the season.
How to keep your greenhouse healthy
- Check your plants regularly for damage and disease.
- Remove dead or diseased plant parts continuously.
- If you discover aphids or mites, you can spray with a mild mixture of green soap water – start with one tablespoon of green soap in 10 liters of water and increase carefully if necessary.
- Throw used soil and plant debris into the compost, but cover with soil to prevent the spread of fungal diseases.
- Avoid strong solvents when cleaning glass or plastic – use mild cleaning agents instead.
Regular cleaning and maintenance
Wash your greenhouse thoroughly at least once a year, preferably in early spring. Remove algae and dust from glass and frames to let in as much light as possible. Use non-scratching tools.
