Content

• To step
• Method 1 of 3: Fast-acting additives
• Method 2 of 3: Using compost and slow release additives
• Method 3 of 3: Know when to add potassium

Nitrogen, phosphorus and potassium are the three main nutrients that plants need to grow. Potassium deficiency requires soil adaptation, be it because of too much water that has flushed out the potassium or because of the plant that has used up everything to flower and produce fruit. Fortunately, many organic solutions exist that enable a quick fix or long-term management. To keep your garden green and get the most from your crop, add potassium when the plants start to flower or when you notice yellow patches. In addition, you can have your soil tested once every one or two years so that you know exactly which things you need to add.

To step

Method 1 of 3: Fast-acting additives

1. Add potassium chloride or potassium sulfate. Potassium Chloride and Potassium Sulphate are natural minerals. Potassium chloride is cheaper, but the chlorine it contains can harm the beneficial microbes that live in the soil of your garden. Potassium sulfate is safer, but a bit more expensive.
   • Check the product label for specific guidelines on how much you can add per square foot.
   • Make sure the product you buy is certified by the Institute for the Assessment of Organic Minerals (OMRI).
2. Try kelp flour or seaweed. Kelp and other types of seaweed are rich in potassium and release it quickly into the soil. You can choose to mix a few handfuls of dried kelp into the soil or spray it with a liquid seaweed spray.
   • Mix about 450 grams of kelp flour per 9 square meters.
3. Try Sul-Po-Mag. Sul-Po-Mag is also called Langbeinite and is the most affordable option. You can best use this when the soil test shows that the soil is poor in both potassium and magnesium.
   • Check the product label to make sure it is OMRI certified and to know the recommended amount per square meter.
4. Only add hardwood ash if you are trying to increase the soil pH. Sprinkle 450 - 900 grams per 9 square meters. Wood ash increases the pH of the soil or reduces its acidity. If you are using wood ash to supply your garden with potassium, it is recommended that you test the pH regularly to make sure the soil is balanced.
   • Do not use wood ash with plants that like acidity, such as azaleas and blueberries.

Method 2 of 3: Using compost and slow release additives

1. Add green sandstone to the soil. Use about 2.25 kg with 9 square meters. Green sandstone releases potassium slowly, so it's better for long-term management than quick adjustments. It also acts as a conditioner and helps the soil retain water.
   • In addition to digging green sandstone directly into your garden, it is also possible to add it to your compost pile to increase the potassium content of your compost.
2. Add granite flour. Granite flour is mined in natural granite mines and is fairly inexpensive. Like green sandstone, it slowly releases potassium, so it won't work well to quickly fix a problem.
3. Bury banana peels in the ground. Cut the husks into small pieces and bury them at a depth of 4 to 5 cm in your soil. The peels will only start to rot over time, causing them to release potassium more slowly than other additives.
   • Adding banana peels directly into the soil will also deter aphids.
4. Improve your compost with banana peels. To increase the potassium content of your compost, you can throw away the waste from fruit and vegetables. Banana peels are best for this, but orange peels, lemon peels, beets, spinach and tomatoes will also make excellent additions.
   • Don't forget that you have to allow compost several weeks or months to "ripen".
5. Keep your compost covered to prevent potassium from leaking out. Use a container with a lid or cover your compost pile with a tarp when not in use. Potassium compounds are water soluble, so rainfall can easily wash them out of the compost pile.

Method 3 of 3: Know when to add potassium

1. Have your soil tested once every one or two years. For most gardeners, having the soil tested by a lab every two years is recommended. If you are a serious gardener looking to get the most out of a crop, then you should get your soil tested every season before you start planting.
   • The results will show whether your soil contains low, medium or high levels of potassium, nitrogen, phosphorus and other nutrients.
   • Search online for a university in the area or other lab dedicated to soil testing, or contact a local expert.
2. Add potassium when your crop starts to flower and produce fruit. If you are growing fruits and vegetables, try to avoid a potassium deficiency by giving your plants an extra amount of potassium when they start to flower. When they flower and produce fruit, plants can use up their potassium stores in a few days.
3. Add potassium when you see signs of deficiency. Signs of deficiency include yellow leaves and brown leaf margins. Discolourations often first occur on older leaves or on leaves that are more at the bottom of the plant. With fruiting plants, such as tomatoes, you may even see uneven ripening or yellow patches on the fruit.
4. Check your plants even more thoroughly if you have sandy soil. Due to its high solubility, potassium can easily leach from the soil, especially in rough and sandy soils. Watch carefully if this poses a risk. If possible, test the soil more regularly.
   • To prevent leaks, adding manure and rotten compost to your sandy soil can help.
5. Watch for signs of magnesium deficiency. By adding more potassium, it is possible that the plant will absorb other nutrients to a lesser extent. Potassium's closest competitor is magnesium, so watch out for yellow spots between the leaf veins. The veins themselves remain green, but the spaces in between turn yellow.
   • If you're adding potassium but notice yellowing or getting worse, buy a supplement containing calcium and magnesium or magnesium sulfate. Depending on the product, you have to either mix it in the ground or spray it on the bottom leaves of the plant.