How to assess your soil

Although Spring sowing season might be some way off, it's never too early to start planning! To celebrate World Soil Day, we've laid out a simple step-by-step guide on how to work out what type of soil you're dealing with to help your planting go smoothly. Here's what you should look out for...

Seedlings growing in soil.

What’s the soil like?

Treat’em mean to keep’em keen - wildflowers thrive in poor low-nutrient soils, where they don’t need to compete with plants such as docks, thistles and nettles. 

Group of people looking at patch of grass.

  • Bully boys - if your site is already dominated by docks, thistles and nettles, it’s likely that the soil is relatively high in nutrients. Clear an area small enough for you to keep free of these bully boy weeds and leave the rest (wildlife likes them too so it's good to have some around!) 
  • Roots - make sure you dig out the fleshy roots of weeds in the area you want to grow your wildflowers, otherwise they will grow back vigorously. Some will seed back anyway but they’ll be easier to deal with.
  • Nutrients - you can try to reduce the level of nutrients in the soil in order to make the site suitable for a diverse range of wildflowers. This can be done by removing a layer of nutrient-rich topsoil (around 6 inches or 150 mm) to get down to the low-nutrient soil underneath. 
  • Grassland - if you are dealing with an area that is dominated by grass, it is possible to remove a layer of turf, but this can be back-breaking work for volunteers with hand tools and can only realistically be done over a small area. You might want to consider hiring a turf-cutter.
  • Large areas - if your site is large, you may want to ask the council to prepare the area to expose at least 50 percent bare earth in preparation for wild flower sowing or the planting of plug plants.
  • Loosen up - seeds will not establish in a soil that is compacted, so it’s important to prepare the soil so that it has a light open texture. This can be done by digging over thoroughly to a depth of 4-6 inches, then treading down and lightly raking over.

Soil moisture

Get down - and have a really good look at the soil. While seeds need to be well watered for them to germinate, the quickest way to kill your seeds is by giving them too much or too little water. 

Foot standing on grass and earth.

  • Well-drained - seeds will germinate best on a fine free-draining soil. If the clay content of the soil is too high, the site may be prone to becoming water-logged, which is not ideal for seedling establishment.  You can potentially improve the drainage by digging in some sharp sand and/or grit. 
  • Sandy soil - although offering good drainage, sandy soil may lack sufficient organic content to give your seedlings the start in life they need. You can improve this by digging in some soil conditioner, such as leaf-mould.
  • Testing your soil - Take some soil in your hand, and squeeze it between your fingers to decide what type of soil you have. Sandy soil feels gritty, clay is sticky, and silt is smooth. The perfect soil ought to have a good mix of all three textures, a so-called loam. It is possible to source seed mixtures suitable for specific soils types, but in general a good loam is what you’re looking for. Don’t get too hung up on this though… as long your soil isn’t too clayey or too sandy you should be alright.

What will I find when preparing my site?

Woman holding palmful of soil.

All soil has weeds and weed seeds in it, so you’ll soon find out what’s in store. Deal with the following plants by digging out or pulling up the whole plant:

  • dandelions
  • chickweed
  • creeping thistles
  • hairy bittercress
  • broad-leaved dock
  • cleavers

The real toughies include:

  • bindweed
  • horsetail
  • couch grass
  • brambles
  • nettles

To get rid of these, use a garden fork to remove as much of the plant as possible. But if you’re defeated by rampant weed growth, you could try growing your flowers in a container. Learn more about weeds.