9 Greenhouse Tips for Beginners – Essential Guides for Gardeners

Last Updated on April 3, 2024 by Real Men Sow

I referenced my most read blog post in Real Men Sow history – 8 Beginner’s Tips for Greenhouse Growing – and how flying in the face of that advice had contributed to the greenhouse’s a sorry state.

This got me thinking, I wrote the original post after a couple of years of owning a greenhouse and refurbing an old greenhouse, using the tips and knowledge I’d picked up along the way. Here I was reflecting again, with lots more learned. Perhaps it was time for an update, so here are some extra 9 greenhouse tips!

9 Greenhouse Tips for Beginner Gardeners

Visit Regularly to Keep the Temperature in the Greenhouse

With the heightened temperatures, a lot can happen quickly in a greenhouse, so make sure you visit regularly to keep a good eye on things. Every day is recommended, but try and get there at least once a day if you can. If you don’t have time, consider getting a greenhouse heater to keep the temperature constant in colder times.

Sideshoots on tomato plants will often appear during the course of a day, and plants can rapidly outgrow their supports and require re-tieing. You won’t want to miss harvesting that juicy red tomato before it goes over either.

Start as You Mean to Go On

With regular visits in mind, start as you mean to go on. Get into a routine from day one, and try and set aside the same time every day to visit. If you can develop a habit, this will help see you through until the end of the season.

Think About the Future

One thing that I regularly overlook is that a greenhouse is for more than just sowing seeds in the Spring. Once those seeds have moved on to their new home in the veg beds, the greenhouse provides an invaluable space for other crops, such as tomatoes and cucumbers, as well as extending the growing season into Autumn. Plan ahead and grow crops for this reason too.

Don’t Over Plant in the Greenhouse

After infrequent visits, this is my biggest mistake of 2019. I’ve tried to cram far too many large plants into the greenhouse, which has resulted in poor crops and an untidy environment. Overgrown plants also prevent good air circulation between plants and encourage diseases such as blight.

When planting out, bear in mind that the plants could grow bigger than outdoor crops due to the warmer conditions, so take spacing advice from the seed packets and add a few more centimeters.

Watering Tips: Water the Greenhouse Plants Well & Consistently

Again, visit daily if you can. A greenhouse will dry out quickly during hot weather, so make sure you’re on top of things. Check the base of the plant to see if the soil has dried out, but keep that water coming before the plants start to wilt. Plant seedlings in grooves to keep the water around the base of the plant. This will channel the water into the roots, rather than running off as the soil hardens.

And when you do water, water well. Don’t (like me this year…) toss a quick watering can full of water erratically over the soil and be done with it.

Greenhouse Tips for all: Control the Weeds

Just like seedlings, weeds will start growing earlier than outside so don’t let them take a grip. Keep weeds down with regular hoeing, and use weed suppressant fabric or cardboard on bare soil. This will rob the weeds of sunlight and prevent them from growing.

Don’t forget the weeds outside of the greenhouse. Keep the perimeter clear to stop weeds coming in under your base.

Choose the Right Plants to Grow

A greenhouse is the place for tender plants such as tomatoes, cucumbers, and aubergines, but definitely not somewhere for plants that go bonkers and take over. Try to resist the temptation to grow butternut squashes (like I did this year…) and courgettes inside unless your greenhouse is of polytunnel proportions.

Open the Door and the Hatch

On very warm days, remember to open the hatch as well as the door as greenhouses can reach incredible temperatures and scorch even those plants that love the heat. By opening the hatch, hot air will be released through the roof to complement the cool air drawn in by the door.