The Beginner’s Guide to Greenhouse Gardening

Are you considering adding a greenhouse to your garden, patio, balcony?  Whether you’re a novice gardener or an experienced green thumb looking to expand your growing capabilities, a greenhouse offers countless benefits that can transform your gardening experience.

Why Invest in a Greenhouse?

A greenhouse can be a game-changer for how you enjoy fresh produce all year round. One of the best parts of greenhouse owning is when I’m mid-cook and realise I need fresh tomatoes, basil, or parsley and there’s no last-minute dash to the shops. Instead, I simply pop out to the greenhouse and pick what I need.

Making a salad for dinner?  I can wait until the very last minute to pick crisp lettuce leaves, cucumber, and juicy peppers – straight from the greenhouse to the plate/pot in under two minutes!  And don’t get me started on the strawberries!  Knowing a delicious dessert is waiting to be picked is the best treat – as long as we get to them before the dog does!  My children love peppers, and eat them like apples, so they like to grab those as a treat.

It’s also a great hobby to get the children involved in when they’re young.  Gardening is a fantastic way to spark their curiosity and they’re more inclined to try new foods if they’ve grown it themselves.  Watching a tiny seed grow into something they can harvest and eat is both exciting and educational.  It not only teaches them where food comes from but also encourages them to try a variety of fruits and vegetables – making mealtimes more exciting and nutritious.   If you’ve followed us for a while on social media, you’ll have seen the pure excitement of a single solitary pear from our pear tree!

Year-Round Growing Potential

One of the biggest perks of owning a greenhouse is the freedom to extend your growing season well beyond what’s possible outdoors.  No matter the climate or time of year, you can grow a diverse range of plants – from enjoying vegetables in winter to nurturing exotic varieties that wouldn’t typically thrive in the UK.

We especially love experimenting with tropical plants like passion fruit, mango, and dragon fruit. While success hasn’t quite come our way yet, the joy is in the journey – and we’re not giving up yet!

Protection from the Elements

A greenhouse offers a safe haven for your plants, protecting them from harsh weather like heavy rain, strong winds, hail, and frost. It also keeps common pests, birds, and rodents at bay, ensuring your plants stay healthy and thriving.

We often bring some of our outdoor plants inside the greenhouse during winter – the salvias are especially grateful for the extra shelter, as are a few of our container rose bushes.  One standout is our Lady Gardener rose from David Austin, which absolutely thrives in the greenhouse!  She is moved back out during the warmer months to thrive in the garden.

Creating Optimal Growing Conditions

A greenhouse offers complete control over your growing environment, naturally concentrating carbon dioxide to help plants develop larger leaves and stronger stems.  Many designs also accommodate automated watering systems, ensuring consistent moisture and saving you time.

My top tip? Invest in automatic ventilation!  It’s hands down our most recommended greenhouse accessory. There’s nothing worse than getting to work and realising you forgot to open the greenhouse windows, only to return to some positively sulky tomato plants.  Plus, it saves you from that classic “dressing gown dash” when you remember – just as you’re heading to bed – that the vents are still open.   Automatic openers will react according to the temperature – so you never need worry about them again!  If you want to read more about how automatic openers work, read our blog How Do Greenhouse Automatic Vent Openers Work?

Therapeutic Benefits

A greenhouse isn’t just a place to grow plants – it’s a sanctuary.  Many hours are taken ‘pottering’ which is possibly my personal favourite thing to do.  It offers a tranquil escape from the stresses of daily life, providing a space for relaxation and reflection – or with a small compact radio to bop to at the same time.  The mental health benefits of greenhouse gardening are truly invaluable.

Essential Considerations Before You Buy

Before rushing into a greenhouse purchase, take time to consider these crucial factors:

Purpose and Goals

What do you plan to grow?  Are you interested in year-round vegetables, exotic flowers, or perhaps starting seedlings earlier in the season?  Your specific goals will influence the size, design, and features your greenhouse should have.  If you’re unsure, give us a call or email and we can advise – Contact Us

Size and Space

Many gardeners often wish they had opted for a larger greenhouse. It’s a common regret, so it’s wise to choose the biggest size your budget and space allow.  You’ll likely discover even more uses for it than you initially expected.  We have never heard anyone say they wish they’d bought a smaller greenhouse.

When planning, carefully measure your available space, considering both floor area and height requirements for taller plants. Keep in mind that greenhouse sizes are typically advertised as nominal measurements – meaning they’re often slightly larger.  For example, a 6×8 greenhouse usually measures around 6’3″ x 8’5″.  A little extra planning now can save you from future frustration.  I personally like the fact that I have around 12″ of extra base around the perimeter of my greenhouse.  I can plant flowers around the edges, which then in turn offer natural shading to the inside of my greenhouse in the summer.  I have cala lillies to the front, along with various flowering plants, roses down one side as well as lillies and mangetout and green beans down the side that gets full sun – this offers shading to the tomatoes inside.

Location and Orientation

Your greenhouse should be placed in a location that receives maximum sunlight throughout the day. An east-west orientation typically provides optimal light exposure, especially during winter months. Avoid areas prone to strong winds if you can, though there are options for greenhouses designed for windy/coastal areas, like the Elite Titan.  Make sure you give particular attention to the type of base you are installing.  We recommend paved slabs as optimal, concrete second, plinths third and then soil.  See our Blog regarding bases here: Let’s Talk Bases.

Budget Considerations

Be realistic about costs – both initial purchase, base installation and ongoing maintenance. Larger greenhouses generally require more heating, cooling, and upkeep.  Consider both the structure itself and additional components like staging, irrigation systems, and potential heating solutions.  Ensure you know what you are getting for your money.  For example, some greenhouses include things like rainwater kits and louvres as standard, but some don’t.  That’s why we provide full written quotations to those who want them – because it’s easier to process what you’re getting for your money when it’s listed on paper/email.  All this said, it is very easy to be successful in your greenhouse growing with just a simple greenhouse with no additional equipment.  My first greenhouse was a Halls Popular – it had no staging or shelving, no automatic openers, no louvres – and I did just fine.  You can always add additional items on afterwards, once you’ve found your feet.

Choosing the Right Greenhouse

Materials Matter

Greenhouses typically come in two main material options:

1. Aluminum: More affordable and naturally resistant to rust, aluminum frames require minimal maintenance but conduct heat more readily, meaning the greenhouse may cool faster in winter.  Most manufacturers offer a range of powder coated options for your preferences, but some more than others.  For example, Juliana are usually aluminium/black or anthractite/black; Halls are usually in Green or Black, whereas Elite offer 10 different options, as well as personalised colours (just provide the RAL number) and also a mix-match option!
2. Wood/Cedar: While more expensive, wooden/cedar greenhouses offer better natural insulation, helping maintain more stable temperatures. They require regular maintenance to prevent rot but provide a classic, attractive appearance.  Mercia Greenhouses also offer multiple painted options.

Ventilation Systems

Proper airflow is essential in a greenhouse to prevent overheating and reduce humidity-related diseases. Look for models with:

• Roof vents (preferably with automatic openers, these can be added at a later date)
• Side vents or louvered windows
• Doors that can be left open in summer (most can, though Juliana offer stable doors, which are great for those with chickens/pets – you can keep the bottom closed and the top open to keep them out).

Setting Up Your Greenhouse

Essential Equipment

To get started, you might want some basic equipment – though as I said earlier, some is really not essential to start with:

• Staging and shelving: Raises plants off the ground for better air circulation and convenient working height (handy but not essential).
• Propagation tools: Seed trays, pots, compost (essential).
• Temperature monitoring: A max/min thermometer to track conditions (handy but not essential unless you’re growing particular plants that need a certain minimum temperature or succulents).
• Shading: Materials to reduce intense summer heat.  This can be via greenhouse paint or internal/external shading.  I tend to plant with planning – I plant taller growing plants on the outside of my greenhouse that gets the most sun.  I grow green beans that grow tall enough on the outside, to protect the tomato plants that are growing on the inside.  That said, I do still have blinds inside the greenhouse.  I like the Halls Internal Shading Blinds – as these can be moved around the greenhouse as needed and are easy to retract.

Layout Planning

People talk a bit about layout planning, but you’ll probably find that you end up moving things around as the season progresses anyway.  For example, peppers may grow on your staging areas to start, but then move onto the floor as they grow taller.

Seasonal Greenhouse Management

Spring

Spring is the busiest time in your greenhouse:

• Sow seeds for summer crops like tomatoes, peppers, and cucumbers (but don’t do it too early!).
• Start hardier plants for later transplanting outdoors
• Monitor ventilation as temperatures begin to rise
• Check regularly for pests

Summer

During warm months, focus on:

• Daily watering (early morning and early evening is best)
• Proper ventilation to prevent overheating
• “Damping down” (wetting the floor) to increase humidity and lower temperature on hot days
• Supporting climbing plants and training vines (I’ve found this to be important – cucumbers can send runners out and if they attach to tomato plants, they could break the stems if not monitored).
• Harvesting early crops
• If you see ladybirds in your garden, move them into your greenhouse – they eat a lot of your pests!

Autumn

As temperatures cool:

• Remove spent summer crops
• Sow winter salads, peas, and broad beans
• Clean surfaces and pots before winter.  Throw away any broken/cracked pots.  They can be stored easily in a pair of old tights and hung somewhere.
• Check heating systems if you plan to grow through winter

Winter

In the coldest months:

• Insulate with bubble wrap to retain heat if you plan on growing through the winter
• Add heating if protecting tender plants
• Minimise watering and watch for dampness
• Use the space to clean and organise gardening tools
• If you have any garden plants that need shelter, move them in.  We have an acer that throws a wobbler in the winter (and every other Friday), so it’s moved into the greenhouse to protect it.

Beginner-Friendly Plants for Your Greenhouse

When starting out, focus on these easy-to-grow options:

Vegetables

• Tomatoes
• Peppers and chillies
• Cucumbers
• Lettuce and salad greens (lambs lettuce is a great option for children to grow)
• Carrots
• Spinach
• Cress
• Kale

Fruits

• Strawberries
• Raspberries
• Lemons
• Blueberries

Herbs

• Mint (be careful, it it invasive so plant in a pot)
• Parsley
• Rosemary
• Thyme
• Basil (can be a bit sulky in warmer weather)
• Sage
• Lavender

Flowers

• Marigolds (slugs are supposed to hate them, so plant between your tomatoes)
• Violets
• Peace lilies
• Salvia
• Cala lillies

Maintenance and Troubleshooting

Regular Cleaning

Keep your greenhouse functioning optimally by:

• Cleaning glass or plastic panels at least twice yearly to maximise light
• Sanitising pots and tools to prevent disease spread
• Removing plant debris promptly
• See our blog regarding Winter Cleaning Preparing Your Greenhouse For Winter…

Pest and Disease Management

Prevention is easier than cure:

• Inspect new plants before introducing them
• Use yellow sticky traps for early pest detection
• Consider biological controls rather than chemicals
• Ensure good air circulation to prevent fungal issues
• Kidnap ladybirds from the garden

Temperature Control

Maintaining appropriate temperatures:

• Use bubble wrap insulation in winter
• Consider soil warming cables for root-level heat
• Invest in a small heater for particularly cold periods

A Note From Us:

A greenhouse opens up exciting possibilities for year-round gardening, protection for delicate plants, and a peaceful sanctuary to enjoy your horticultural hobby.  While there’s much to learn, start simple and expand your knowledge as you gain experience.  But don’t overthink it!  Remember that greenhouse gardening is accessible to gardeners of all skill levels.  Whether you’re looking to extend your growing season, experiment with exotic varieties, or simply enjoy gardening regardless of weather, a greenhouse provides the perfect environment to nurture your passion (and escape the children).

Happy greenhouse gardening!

Catherine
TGS