It’s easy to overlook the importance of pollinators when planning out your greenhouse.

I totally get it. For me, the first year I had my high tunnel, I was just focused on filling every inch of the space with heat-loving plants. I had this vision of enriching the soil and maximizing every square foot with edible produce.

But I was missing something. The idea of inviting pollinators into my high tunnel never even crossed my mind—until I found myself with cucumbers and zucchini growing flowers but not producing any fruit.

It was pretty disappointing.

Obviously, some plants need the work of pollinators to bear fruit and produce viable seeds.

But inside an enclosed space, that connection is easy to miss. At least it was for me. It's a closed world, with no natural wind and no open doors for crucial pollinators to come and do their thing.

Even self-pollinating plants like tomatoes and eggplants thrive even more with visits from bumblebees (MSU).

That was a turning point for me. As I learned about the importance pollinators for certain plants, I started to be more mindful about what I grew in my greenhouse.

I’m happy to share that I was able to transform my greenhouse into a bustling haven for wasps, bumblebees, hoverflies, and even butterflies.

I'll share the practical ways I keep these vital visitors happy and productive, so they can help my plants to live their best life.

Whether you're planning ahead as you decide if you should buy your own greenhouse, or just looking to up your game, my insights and tips will help your crops to thrive.

Benefits of a Pollinator-Friendly Greenhouse

In our changing world, it’s more important than ever to create pollinator-friendly areas in as much of our yard as possible. Declining insect populations mean that any effort - no matter how small it seems - can make a difference.

You can actively contribute to reversing the trend and support biodiversity. Plus, in addition to personal satisfaction, you’ll get increased crop yields and improved fruit quality.

How To Grow Plants in Your Greenhouse That Will Attract Local Pollinators

Positioning:

It’s important to consider what an insect can sense is growing from an enclosed space.

Place some plants at the entrance: Last year, I found that having some bachelor’s buttons, alyssum, and strawflowers at the entrance of my hoophouse. It's kind of like a welcome mat, helping the pollinators to feel at home.

Place some plants towards the very back: I also like to always have herbs and flowers in the back of my greenhouse so beneficials stop by the other crops on their way in and out. Calendula, rosemary, and scabiosa were in the back this past year.

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Hydration:

Since whatever is inside a greenhouse doesn’t get rain, it’s important to make sure your insect visitors have access to water. This is especially true if you’re working with drip irrigation, since no overhead watering means insects can’t access water drops on leaves.

• Make a Bee Drinking Station: I place a shallow dish filled with water and pebbles near plant clusters. I’m sure to refresh water regularly to prevent stagnation and mosquito breeding. Check out my DIY Bee Drinking Station Guide for more info.
• Add in a Butterfly Puddling Zone: Butterflies seek out mineral-rich water to help them get the nutrients they need. Some salt, rocks, or even fruit added to a dish of water will make it extra attractive to butterflies. The National Wildlife Foundation has a guide on that here.

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Proper Exit:

It’s just as important that beneficial insects can leave your greenhouse whenever they please. I’ve noticed that without plenty of exit locations, unfortunately the insects can get stuck inside and die.

Here’s how I avoid that:

• Summer Ventilation: In the summer, I always open doors, sides, or windows during daylight hours. The plants appreciate the airflow, too.
• Plants Marking Exits: I have some pollinator favorites, like oregano and marigolds near the sides of my high tunnel, which roll up so that insects can be guided towards the exit.
• Have Rescue Equipment: Keep a large cup or lightweight pot and a sheet of cardboard nearby to help catch and release any stuck butterflies or insects.

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Mix it Up:

Integrate flowering plants into your undercover edible plantings. Think of them as companion plants, helping your enclosed ecosystem to be as productive as possible.

• Prioritize Native flowers: Marigolds, echinacea, rudbeckia, asters, beebalm, and anise hyssop are all great candidates for greenhouse growing.
• Be mindful of spread: Hardy spreading herbs like mint, nettles,  chives, catmint, and catnip should be grown in containers.

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Year-Round Food Source:

Just like you would in an outdoor pollinator patch, grow plants in your greenhouse that bloom at different times to ensure year-round attraction.

• Early Long-Lasting Bloomers: I like to plant calendula and chamomile as early and long blooming plants in my polycrub. As I write this in late December, these two plants are still in flower!
• Summer: Cosmos and sunflowers make for excellent mid-summer flowers for bees and bouquets
• Autumn: Echinacea and rudbeckia are my top picks for autumn forage - plus they’re perennials so you only need to plant them once.
• Cover Crops: Bees also appreciate when my greenhouse cover crops, like hairy vetch or daikon, are in bloom. This provides early-season forage which is especially important for the queen bees, who are the first to venture out of hibernation in the spring.

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Let Herbs and Vegetables Go To Seed:

Bees really love when you let herbs, leafy vegetables, and flowering vegetables go to seed. In the process, the flowers they produce are an insect-magnet. Many of the herbs and vegetables that I grow in my greenhouse, when in bloom, lend themselves well to serving as insect forage once their main harvest window is complete.

• My Top Herb Picks: I’m okay with letting herbs like basil, oregano, cilantro, or mint go to flower. Even though it turns the plant leaves bitter, the flowers from these plants are very attractive to beneficial insects.
• Beneficial Insects Favorite Vegetables: Broccoli, lettuces, onions, or leeks are magnets to a whole variety of native bees when they set flower. I’m always blown away by the number of bees that go to my broccoli blooms, or the swallowtail butterflies who rest on the onion flower orbs.

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Create Winter Shelter:

Did you know that beneficial insects and butterflies naturally overwinter in certain types of environments? Part of creating a pollinator habitat in my high tunnel also includes creating comfy spaces for them to rest up and overwinter.

• Add Mulch: Either with chop and drop or by bringing in autumn leaves, plant litter like this is like a cozy winter bed for bees and butterflies.
• Leave Stems: Some pollinators, like carpenter bees and leafcutter bees will make a hollow stem their temporary winter home. Plants with hollow stems, like elderberry, fava beans, motherwort, or fennel are ideal. Learn more from the Xerces Society.
• Grow Larval Host Plants: Butterflies lay their larva on or near certain plants, so that they have a guaranteed food source when they emerge. Grow plants like nettles (in containers!) and fennel, or let a few carrots stay behind so they will make a flower in early spring.
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Tips for Success:

• Organic Practices: Use natural pest control methods like beneficial insects or neem oil. While I totally understand that you want to get the most food out of your greenhouse garden, synthetic chemicals will be a detriment to your ecosystem.

• Consistent Watering: Water plants consistently to reduce stress and improve nectar quality. This is especially important here, where evaporation can happen quickly.

• Remove Invasive Plants: Regularly inspect for and remove invasive plant species. These plants can really multiply, especially in the warm conditions.
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Observation: Monitor Insect Diversity and Health

A wildlife survey can help you to understand what's working well in terms of insect visitors, and what may need to be adjusted.

• Keep a journal or logbook noting the different insects you see over time.
• Spend a half hour sitting in one spot and take photos of different insects as they visit your plants. I find that this helps me research and identify them a lot easier. It’s also like a visual diary of my greenhouse’s ecosystem.
• Make adjustments based on which plants or practices attract the most diversity.

With these strategies in place, I was able to finally get harvests from my zucchini and cucumbers, and my tomato yields improved too. Watching the paper wasps make themselves at home (and never sting me!) at the entrance of my greenhouse was always interesting. Seeing a swallowtail butterfly rest on a tomato plant was a moment of awe and wonder.

It’s fascinating how the symbiotic relationship we share with nature is something that can be encouraged through sustainable practices.

With this plan, you’ll experience the joy of watching your garden thrive with an active pollinator population.

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FAQ:

Do greenhouses actually need pollinators?

While greenhouses are often designed to control environmental conditions and may seem self-sufficient, many plants grown inside still require pollinators to thrive.

Pollinators play a crucial role in the fertilization process of many fruits and vegetables. While some plants are self-pollinating, others depend on external agents for successful reproduction.

Even self-pollinating plants like tomatoes and peppers can benefit from the presence of pollinators, which can increase yields and improve fruit quality.

In essence, even though it might be possible to grow some plants without pollinators in a greenhouse, incorporating them can lead to healthier and more productive crops.

Pollinators also contribute to biodiversity, making greenhouses more sustainable and ecologically balanced.

How to manage pests without harming pollinators?

Managing pests while protecting beneficial insects requires thoughtful organic strategies:

1. Use Organic Pesticides: If chemical intervention is necessary, opt for organic options like neem oil or insecticidal soap, which have minimal impact on pollinators when used correctly.
2. Implement Physical Barriers: Use nets or row covers to protect plants from specific pests. This method physically keeps pests away without affecting bees.
3. Enhance Plant Health: Healthy plants are more resilient to pest attacks. Practice good cultural tactics like crop rotation, proper spacing, and adequate watering to keep plants robust.

Will any flower work to attract bees?

Not all flowers are equally effective at attracting bees. They prefer flowers that offer high-quality nectar and pollen, with some characteristics being particularly appealing:

1. Color: Bees are especially attracted to bright colors like blue, violet, and yellow.
2. Single Flowers: Opt for single-flowered varieties rather than double-flowered hybrids. Single flowers usually have more accessible nectar and pollen.
3. Nectar and Pollen Richness: Plants like lavender, borage, and marigolds are known for their high nectar and pollen yield, making them favorites.
4. Native Plants: Native flowers are adapted to the local ecosystem and are typically more attractive to local bee species.

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Before you go…

Check out my buying guide for small greenhouse kits perfect for home gardens

Have a look at my Bee Gardening 101 Guide for more pollinator plant ideas

Learn how Bee Gardening attracts other beneficial insects for natural pest control

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