Whether you are growing flowers in beds, borders or planters, using the right soil will give you better results. In this blog we look at which soil is best for growing flowers.
What to look for in garden soil for flowers?
- Free from large stones and debris
- No chemical contaminants
- Water retentive but not soggy
- Packed with nutrients for cultivated flowers
- Use low nutrient soil for herbs and wildflowers
- Easy to work with
Some flowers are a little fussy about soil types and pH but in general, most plants are happy with a good quality topsoil. Let’s look at soil quality in a little bit more detail.
Free from large stones and debris
Large stones and debris such as plant roots, decaying wood and man-made rubbish are a definite no-no for growing flowers. They can block the root-run and impede drainage.
If you are buying soil, you need to be paying for useful growing medium – not for rocks – so choose your supplier wisely and ask for screened topsoil.
Screening is basically passing soil through a giant sieve to take away huge particles. 20mm screening means that you won’t receive any stones or debris with a diameter greater than 2cm (about the size of the top of your thumb)
No chemical contaminants
Chemical contaminants can’t often be seen. Sometimes you can smell them – but not always. Some chemicals can damage plants, some can damage people or watercourses. Ask your supplier for a certificate to prove that their soil has been tested for contaminants.
Water retentive but not soggy
Unless you are growing bog plants or pond marginals, your flower plants will probably not appreciate being in waterlogged soil.
Make sure, if you are using planters, that there are drainage holes in the bottom. Add a layer of gravel, pebbles or crocks (broken pots) before the soil to make sure that the drainage holes don’t get blocked. This will also ensure the soil doesn’t wash out of the bottom of the pot.
On the other hand, soil for growing flowers should not be too well drained. If it is very sandy, you’ll be watering 24/7 during a hot summer.
Improve the water holding capacity of soil by adding some water storing crystals. Simply work them into the soil and plant as normal.
Packed with nutrients for cultivated flowers
Flowering plants need a lot of plant nutrients if you are to get really good floral display. It’s especially important that the soil they are growing in is a good source of Nitrogen, Potassium and Phosphorus.
You will probably want to add supplementary feeds during the flowering season. However if you have good soil to start with, the plants will be more forgiving if you should forget.
The exception to this is wildflowers. They like a low nutrient soil – more on that later.
Look for a dark brown colour – that normally indicates that there is a lot of organic matter in the soil. Good for water retention and nutrient content.
Is it OK to use peat-based soil for growing flowers?
It’s up to you whether or not you choose to use peat. However it is a finite resource and harvesting peat is thought to damage the peat bogs that help protect us from climate change.
A good quality topsoil is just as good, if not better than peat in planters and hanging baskets.
Why use low nutrient soil for herbs and wildflowers
Some plants are just not adapted to high nutrient soils and that applies to most UK wildflowers. If you are sowing wildflower seed, planting plug plants or laying Meadowmat wildflower turf, invest in some low nutrient soil to give them the conditions they need to succeed.
What soils are easy to work with?
Much as I love gardening, I hate backache and I don’t like having my hands chapped by abrasive soil particles.
When you are buying topsoil, look for something with relatively small proportions of sand and clay. Those two soil constituents have many benefits but being light weight is not one of them.
For me, the best soil for growing flowers is this screened topsoil from Turfonline. It’s peat-free, contains lots of organic matter and it’s easy to work with. The generously sized bag contains a good cubic metre of soil – you can fill lots of containers with it, or use it as a soil improver in beds and borders. This makes it the best soil for gardening and growing flowers!
You’ll find out more about soil workability in our recent blog about vegetable gardening.