After planting your veg out in the spring, you will soon be able to see if your soil is nice and nutritious as the leaves of your plants will stay a lovely vibrant green. If you spot any discolouring, then you may find your soil is lacking in certain minerals. Below is a quick snapshot of some of the most common deficiencies and how to recognise them:
- Magnesium deficiency – this manifests in the lower, older leaves turning yellow gradually from the tip of the leaf inwards. The veins remain green.
- Nitrogen deficiency – the newer, upper leaves turn a pale green and the lower leaves turn yellow.
- Potassium deficiency – the edges/rim of the leaves turn yellow on newer leaves.
- Calcium deficiency – you’ll see curled or misshapen leaves
- Phosphorus deficiency – older leaves will turn a dark green, and eventually turn purple or red.
- Manganese deficiency – white/pale yellow blotches and spots on leaves.
So what do you do if you see any signs of nutrient deficiency? There are three key things to address:
- Is there enough moisture in the soil? If the soil is too dry (or too waterlogged) the plant will be unable to draw the nutrients up out of the soil. So the first step is to ensure that the moisture levels are right – not too dry, and not too wet!
- Is the soil temperature ok? This is another thing to consider. If it is very cold, or very very hot, then this can cause stress to plants and they are unable to get the nutrients they need. If it is cold, consider putting fleece or cloches over plants. If it is too hot, a mulch will help to keep the soil temperature more consistent.
- Add some food. This is the final step – you may need to actually replenish the soil with nutrients. You can do this by sprinkling worm cast fertiliser on the soil and watering it in. You can add a compost mulch. You can make a liquid fertiliser by soaking comfrey or nettles in water for a day or two, or use an organic liquid feed. All these will help to put vital minerals back into the soil.