Practical guide
Know your garden
Three things shape what grows where you live: your soil type, your soil pH and your hardiness zone. Here is how to find each of them, from a free test in five minutes to a lab analysis you do once.
Why these three numbers matter
Some plants really do choose your garden. Weeds and self-sown seedlings settle exactly where the conditions suit them, which is why they tell you something about your soil for free. The plants you pick yourself do not get that choice: they thrive or sulk on whatever they find. Soil type controls drainage and how much air reaches the roots. Soil pH decides which nutrients are available. Your hardiness zone tells you which species survive your winter. Set all three in your garden profile and the plant finder in Gardiflora filters on what suits your soil and ranks on pH and hardiness.
Soil type: sand, loam or clay
Soil texture is the mix of sand, silt and clay particles. You do not need a lab to find out where you land. The feel test takes under a minute: take a moist handful and rub it between your fingers.
| Property | Sand | Loam | Clay |
|---|---|---|---|
| Drainage | fast | moderate | slow |
| Warms up in spring | early | average | late |
| Holds nutrients | poorly, feed more often | well | very well, but compacts easily |
| Feels like | gritty | smooth and floury | sticky, holds a ball |
The ribbon test
Roll a moist handful into a sausage and squeeze it upward between thumb and forefinger. The longer the ribbon gets before it breaks, the more clay you have.
- Sand
- No ribbon at all. The soil crumbles apart as soon as you squeeze.
- Loam
- A short ribbon that breaks under 2.5 centimetres.
- Clay
- A long, flexible ribbon of more than 5 centimetres.
The jar test
Want a number rather than a feel? Fill a clear jar one third with soil, top up with water, add a teaspoon of dish soap to break up the clumps, shake hard and let it stand for 48 hours.
Measure each layer with a ruler and divide by the total height. That gives you your texture as a percentage.
Soil pH: how acidic or alkaline is your soil
pH decides which nutrients your plants can actually take up. Iron locks away in alkaline soil, which is why hydrangeas turn pink there.
Five ways to find your pH
You do not need a lab straight away. Start free and measure more precisely only when you need to.
| Method | Cost | What you get |
|---|---|---|
| Reading the weeds | free | Sorrel, plantain and field horsetail point to acid soil. Wild mustard, poppies and chicory point to alkaline. A direction, not a number. |
| Vinegar and baking soda | kitchen cupboard | Pour vinegar on a sample: if it fizzes, your soil is alkaline. Mix a second sample with water and baking soda: if that fizzes, your soil is acidic. |
| pH strips or a home kit | around 10 euros | Mix with distilled water, not tap water. Accurate to about half a pH unit, which is plenty for choosing plants. |
| Electronic pH meter | 20 to 50 euros | Handy for many readings in a row. Cheap models drift and need calibrating with buffer solutions. |
| Lab analysis | 30 to 80 euros | You get pH, nutrients, organic matter and often texture too. Worth doing once for a new garden or a stubborn problem. |
Hardiness zone: which plants survive your winter
A hardiness zone is the average annual minimum temperature where you live, banded into numbered zones. The lower the number, the colder. In Western Europe almost every garden sits between zone 7 and zone 8.
| Zone | Where | How you can tell |
|---|---|---|
| 6 | Higher ground and continental inland areas | Only the hardiest natives make it through winter. |
| 7 | The Netherlands, Belgium, northern France and most of Germany | The standard for this region. |
| 8 | Western and coastal France, southern England and Ireland | Figs and rosemary overwinter outdoors. |
| 9-10 | Southern France and the Mediterranean | Olives simply live in the garden. |
Where to look your zone up
- Belgium · KMI/IRM
- France · Météo France
- Germany · Deutscher Wetterdienst
- United Kingdom · Royal Horticultural Society
Search for your town with 'hardiness zone' or 'plant hardiness'. For your actual microclimate, a min-max thermometer kept in the garden over a few winters says more than any map. A walled town garden often runs one zone warmer than the open countryside ten kilometres away.
Put it into your garden
Once you know your soil type, soil pH and hardiness zone, set them in your garden profile in the Gardiflora app. From there the plant finder filters and ranks on your conditions, and plants in your garden that do not match get a warning. If your numbers turn out to be at an awkward extreme, the answer is not always to amend the soil. Picking plants that already love what you have is the ecological short-cut, and it always wins.
