*Important: Heavy limits apply for this product. Please note limit 2 bags per order due to shipping weight*

*This is a 'heavy item' which has a limit of 2 bags per order if there's nothing else marked heavy in your order, as although the bag is small, lime is heavy! You can add other items to your order as usual. Limits only apply to items marked heavy.

Calcium is essential - yet it's rare to find fertiliser with calcium included, let alone enough to meet the demands of indoor plants (especially calcium lovers like Peperomia). That's because calcium is NOT a mobile nutrient. You know when an old leaf goes yellow? When there's a nutrient deficiency, yellowing leaves are your plant shifting mobile nutrients from old leaves. Sacrificing old leaves to support new leaves, until you (hopefully) correct what they're deficient in. But our plants can't do that with calcium. Once there's a calcium deficiency, it's a deficiency for life for that root, leaf, stem or bud that formed without enough, because Calcium is not a mobile nutrient.

What are the signs of a calcium deficiency?

Unlike many other deficiencies - which tend to impact old growth first - when it comes to calcium, the signs will appear on new and younger growth first. Common symptoms are smaller leaves, deformed  or misshapen growth, and crinkled, split or torn leaves & leaf edges. New buds may fall off before flowering, and buds may turn out to be rotted inside. What you won't often see however is the impact not enough calcium has on the growth of root tips. 

What plants need calcium?

Calcium is an essential nutrient. That means all plants need calcium. However some are known as 'calcium lovers' because they show the signs of a deficiency more than others, need more than others, or need lime added to keep substrates like bark from rotting over time. These include Orchids, African Violets, Hoya, Peperomia, Kalanchoe, Spider Plants, Ivy, Tomatoes, Apples, Lemons and more. 

What about using other calcium sources like milk or eggshells?

Milk or 'milk water' is not recommended for indoor plants. It can attract fungus gnats (who love rotting organic material), as well as fungus and mould.  Eggshells are also often suggested to increase calcium, however used indoors they break down slower than outdoors, if at all. In compost and outdoor gardens, eggshells take around 3 to 5 years to break down. More about eggshells here

How do you use dolomite lime for indoor house plants?

As dolomite lime is more often used outdoors, to prevent or correct calcium and magnesium deficiencies in fruits and fruiting trees (like Tomatoes and Apple Trees), you'll see the directions on the bag are based on square metres of soil. Directions are not given for indoor plants on the bag, however ask and the internet provides...

How much dolomite lime to add to potting mix:

Add about one tablespoon of lime per 5 litres of dry potting mix. Mix in thoroughly before potting up. Dolomite lime is slow release over 2 to 3 months, so reapply about quarterly, three to four times a year, if needed. Potting mixes high in bark benefit from lime to keep from rotting over time.

How much dolomite lime to add to an established plant:

If already dealing with a calcium or magnesium deficiency, you can add dolomite lime to a plant without repotting. For seedlings and baby plants: mix lime in with the potting mix (see above). For smaller pots around 11cms to 14cms: Sprinkle about 1 teaspoon of lime evenly over the surface of dry potting mix. Use a fork to mix in well, into the top layer of the potting mix. Water as usual. Reapply every 2 to 3 months if still seeing signs of a deficiency or need to adjust soil pH. For medium to larger pots, around 15cm to 20cm, follow the same directions as smaller pots, however increase to around 1.5 to 2 teaspoons of dolomite lime. 

How often should you add dolomite lime to houseplants?

Dolomite lime is a slow-release source of calcium and magnesium, gently increasing levels available to the plant while adjusting soil pH to a healthy range. You can reapply dolomitic lime every 3 months or so depending on watering. The more often you water, the faster the lime will be washed out and used up. It's advised to test your soil before each application to check pH level. If needed, apply about two monthly in higher-watering times of year or frequently watered plants, otherwise every three months.

How big is the bag?

Yates Dolomite Lime comes in a 2.5kg bag (the smallest size available), which measures about 14cm x 19cm x 7cm. One bag will be plenty for the majority of house plant hobbyists. The bag is resealable. Being essentially rock, it doesn't 'expire' but should be kept sealed in a cool, dry place indoors. A little goes a long way! 

Safety precautions

Dolomitic lime is not as harsh as other forms of lime, but should still be handled with care. Wear gloves, a dust mask and safety glasses as the powder is quite fine. Mix in well with soil for best results. Avoid breathing in dolomite lime. Avoid contact with eyes and skin. Wash hands after use. 

More details about dolomite mine as well as directions for use >