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As we increasingly recognise the importance of sustainable practices in all aspects of our lives, gardening is no exception. Particularly when it comes to cultivating our beautiful dahlia beds. If you're a nature-loving and environmentally conscious flower gardener who's excited by the idea of growing sustainable seasonal dahlias, this guide is for you.
If you prefer to watch rather than read, here is a video I recorded on preparing my dahlia beds.
Dahlia bed preparation is pretty minimal in general. The soil should be free draining with plenty of organic matter included. Dahlias like to have 6 hours of sunshine a day and once they start growing they will need staking.
Understanding the importance of sustainable gardening
Sustainable gardening is about more than just creating a beautiful space. It's about working harmoniously with nature to create a healthy, productive garden that not only looks great but also enhances biodiversity, improves soil health, and conserves resources. To that end I adopt a lot of the principles of the no-dig gardening approach to create and maintain my cut flower dahlia beds.
In fact, I treat all my cut flower beds the same and they reward me with needing very little extra attention, in regards to watering and fertilisation, throughout the growing season.
Choosing the right location for your dahlia bed
Dahlias love basking in the sun! To help them bloom beautifully, it's best to give them a sunny spot where they can enjoy at least 6 hours of direct sunlight each day.
But remember, in really hot climates, your dahlias might appreciate a little afternoon shade. This way, they can enjoy a cooler afternoon while staying healthy and vibrant, with hopefully less watering required.
Here in the UK, our problem is usually not having enough sun, rather than too much! I've tried planting dahlias in slightly shady spots and, to be honest, they're not quite as happy. For maximum productivity, a spot in full sun is your best bet.
That said, dahlias are pretty productive and can still put on a good show in less than ideal spots. So, if you're okay with slightly fewer blooms, take the risk of planting a dahlia wherever you want to add some wow to your flower bed.
How do you prepare the ground for dahlias?
Dahlias are not particularly fussy about soil type, but they do best in a well-draining soil, rich in organic matter. If your soil is heavy clay, like mine, consider amending it with compost or well-rotted manure to improve its structure and fertility.
Dahlias don’t like to sit in water. Although they are hungry and thirsty plants, too much water can rot the tubers. If you are at all concerned with your soil conditions throw some grit into the hole when you plant it.
My soil is heavy clay, and after following the no-dig approach for several years, my soil is much improved and I have had no problems growing dahlias. My maintenance is minimal, I rarely water them and I don’t provide extra fertilisation. My only issue is slugs & snails.
What do I add to my dahlia beds?
If you are not following the no dig approach then it may be useful to add a mix of high-quality compost or well-rotted manure, a sprinkle of bonemeal, and a balanced organic fertiliser (found on Amazon) to your dahlia bed. Add this as a top dressing, rather than digging it in, although if you are feeling energetic then go for it. Over the course of the season the worms and weather will work the nutrients into the soil either way.
However, as I mentioned previously, I follow the no dig approach, which involves adding a layer of organic compost onto your dahlia bed once a year. This is treated like a mulch, so covers the soil surface. This not only provides essential nutrients for your dahlias, but also improves soil health, promotes beneficial soil organisms, and helps conserve water.
I tend to apply this top dressing in late winter, so I can take full advantage of it as a mulch.
When do I plant dahlias?
If you're wondering about the right time to plant dahlias, it's important to wait until the danger of spring frosts is gone.
I start growing my dahlias in March by potting them up into pots and leaving them in an unheated greenhouse to sprout.
Once the risk of frost has passed, usually mid May for me here in Shropshire in the UK, I will have some nice healthy plants ready to get into the ground.
I find that planting tulips and dahlias in the same bed has a nice synchronicity. The tulips need to be planted after the first frosts, just when you are lifting your dahlias and are usually finished just after the last frosts. Again, just when the dahlias need to be planted.
Tips for growing your dahlias
- Divide your dahlias: To produce good sized productive dahlia plants, it is a good idea to divide the tuber every few years. If the tuber is too large, then you get increasing amount of foliage and poorer quality blooms.
- Starting your dahlias: From March onwards you can start your dahlias tubers growing in pots in a protected growing space. The space doesn’t need to be heated, but it does need to have light and be protected from frost.
- Propagate your dahlias: Once your potted up dahlias start producing more than 5 new shoots you can take cuttings of any of the extra cuttings, to create new plants that will flower and create a tuber within this growing season.
- Pinch out shoots: Once you have stems that have a few sets of leaves, then pinch out the growing tip. This will encourage the plant to produce more lateral growth and flowering stems.
- Planting: When planting your dahlias, plant out the plants deep enough to cover the tuber. Place the tubers about 15cm (6 inches) deep. Space the tubers/plants about 40cm – 70cm apart. Only plant out once the risk of frost has passed. In the UK this is generally mid May.
- Watering: After planting, water them in well. After the initial watering, I prefer to water all my plants (if I need to water) with a long deep drink, rather than a light consistent watering. I think this encourages the plants to go in search of their own water, making them more drought tolerant.
- Provide support: Dahlias, especially tall varieties, will need staking or other support to prevent them from toppling over under the weight of their blooms. It is best to get this in place before you need it, rather than waiting until it is too late.
- Protect from pests: Avoid chemical pesticides in your dahlia bed. Instead, encourage beneficial insects, try companion planting, use physical barriers, or try homemade, eco-friendly sprays.
- Protect from frost: In the autumn, after the first frost, either cut back your dahlias and mulch heavily to protect the tubers over the winter. Or lift them and store them somewhere cool and dry overwinter.
The impact of your sustainable dahlia bed
Creating a sustainable dahlia bed is not only satisfying for you as a gardener but also has a positive impact on the environment.
Your dahlia bed can provide food and habitat for beneficial insects and pollinators, promoting biodiversity.
By using organic compost and avoiding synthetic fertilisers, you can help to build healthy soil teeming with beneficial organisms.
Your sustainable gardening practices can have a ripple effect, improving the health of your local ecosystem.
Creating a sustainable dahlia bed is a journey of love for the environment and passion for gardening. As you watch your dahlias bloom, you'll feel a deep sense of satisfaction knowing that your garden is not only beautiful but also a haven for biodiversity. As the renowned horticulturist, Luther Burbank once said,
“Flowers always make people better, happier, and more helpful; they are sunshine, food, and medicine for the soul.”
Luther Burbank
And Dahlias most definitely do that for me.
This guide has hopefully answered your question on how to prepare a healthy garden bed for dahlias and provided an in-depth look into the process of creating a sustainable dahlia bed.
