Growing a vegetable garden in limestone soil

Chalky soils aren't always popular with gardeners. Stony, dry, and poor... yet these lands can be very productive!

How to recognize calcareous soil?

Limestone soil has a pH above 7, and is considered basic or alkaline. The many white stones that usually litter the surface of these soils are not always visible, but the soil is generally light in color, due to the high proportion of calcium carbonate.

Elms, elderberries, poppies, cowslips, wild chicory, wild mustard, and common fumitory are "calcicole" plants, which "like" limestone. If you see them in your garden, your soil is probably predominantly limestone!

To test this, try it yourself! Pour a few drops of vinegar onto a handful of soil. The limestone will react when it comes into contact with this acidic substance! You'll notice a greater or lesser degree of effervescence depending on its content.

If you want to determine the acidity of your soil more precisely, have a soil sample analyzed by a laboratory.

What are the particularities of a calcareous soil?

These soils are generally light but sometimes heavy limestone soils are encountered.

Limestone soils retain little water. They become dry in the summer, and the often abundant stones can make tilling the soil tedious.

Limestone is an important element. When roots come into contact with it, they extract the minerals they need. Soils with low lime content are fertile, but excess calcium carbonate makes iron, manganese, and magnesium inaccessible to plants. A lack of these essential elements causes some plants to suffer in calcareous environments. In these soils, abnormally yellow leaves are often observed, a symptom of iron chlorosis. This is the case with raspberries and strawberries.

However, limestone soils are not such bad soils!

Their porosity gives them the advantage of evacuating water very quickly in the event of heavy rain or flooding. This property is an asset for plants sensitive to diseases and fungi that thrive in humid environments!

In spring, warm air circulates easily in these lands and quickly increases the soil temperature.

How to cultivate calcareous soil?

Add organic matter! If the plant can't extract the minerals it needs on its own, you need to provide them in another way. By regularly adding a large amount of organic matter (compost, etc.), you will help the soil improve its water and nutrient retention capacity.

Mulch again and again! Organic mulch will retain soil moisture, which easily escapes from chalky soils.

Use green manures! Clover, vetches, and lupins are very effective. They fix atmospheric nitrogen and return this precious element to the soil so that plants can then absorb it. As they decompose, green manures will provide organic matter.

What to sow or plant in chalky soil?

Brussels sprouts, cauliflowers, cabbages in general, turnips, and rutabagas thrive in calcareous environments that protect them from the fungus Plasmodiophora brassicae, also known as clubroot.

Asparagus, beets, parsnips, radishes, spinach and lettuce will tolerate slightly calcareous soils.

Yarrow, mugwort, centaury, poppies, evening primrose, poppies, larkspur, primroses, lavender, baby's breath, bellflowers, carnations, geraniums, valerian, marjoram, rudbeckias, rockroses, rosemary, sage, thyme and a large number of rockery plants appreciate these basic soils.