Using Hydrated Lime in the Garden Safely and Effectively

Hydrated lime is a type of lime product used for various purposes, including gardening. It can be used to raise soil pH in acidic soils and provide calcium. However, hydrated lime is caustic and requires safe handling. This article covers the differences between hydrated lime and agricultural lime, how to use hydrated lime properly, and safety precautions when using it.

Hydrated Lime vs. Agricultural Lime

Hydrated lime, also known as calcium hydroxide or slaked lime, is made by mixing quicklime (calcium oxide) with water. The resulting material is a dry white powder.

Agricultural lime contains calcium carbonate and is made from pulverized limestone or seashells. It is the preferred liming material for improving soil pH in gardens and farms.

The key differences between hydrated lime and agricultural lime:

• Chemical composition – Hydrated lime is calcium hydroxide, while ag lime is calcium carbonate.

• pH raising power – Hydrated lime is more powerful and quicker acting It raises pH more rapidly

• Application rate – Hydrated lime is applied at lower rates, about half to three-quarters that of ag lime.

• Safety – Hydrated lime is caustic and requires careful handling to avoid burns. Ag lime is safer to handle.

• Cost – Hydrated lime tends to be more expensive than agricultural lime,

While both can raise soil pH, ag lime is usually the preferred choice for improving garden soils. Hydrated lime has specialized industrial uses.

Using Hydrated Lime in the Garden

Hydrated lime can be used to increase soil pH for acid-loving plants. Here are some tips if using it in the garden:

• Test soil pH first to determine the need for lime. Desired pH will depend on crops grown.

• Apply hydrated lime at half to three-quarters the rate of ag lime to achieve similar pH shifts.

• Thoroughly mix hydrated lime into the top 6 inches of soil before planting.

• Water lightly after application to begin the pH change reaction.

• Allow 2-4 weeks for the lime to fully react before planting.

• Retest soil pH after a few months and reapply if needed.

• Use caution and protective gear when handling hydrated lime to avoid skin burns.

• Store in sealed containers in a dry area away from children and pets.

When applied correctly, hydrated lime can provide a rapid pH boost for soils needing a change to grow specific crops.

Crops That Benefit from Hydrated Lime

While ag lime works well for most gardens, some crops prefer the quick pH shift hydrated lime provides:

• Blueberries – Prefer a strongly acidic soil with a pH of 4.5-5.2. Hydrated lime can rapidly lower pH.

• Azaleas and rhododendrons – Require a pH below 6, making hydrated lime useful for acidifying soil.

• Potatoes – Scab disease is reduced in acidic soils, so hydrated lime helps create suitable growing conditions.

• Legumes – Beans, peas, clover, and alfalfa need extra calcium that hydrated lime provides.

For these crops, the fast pH change from hydrated lime lets plants access soil nutrients right away for best growth.

Using Hydrated Lime as a Pesticide

In addition to affecting soil pH, hydrated lime can also be used as a natural pesticide:

• Mix 1 cup hydrated lime per gallon of water and spray on plant leaves to deter soft-bodied insects like aphids, mites, and caterpillars. Avoid spraying open flowers.

• Lightly dust dry hydrated lime on the soil around plants to create a barrier for crawling insects.

• Add a thin layer to the tops of garden walls and fences to deter climbing pests.

Always follow label precautions and reapply after rain when using hydrated lime as a pesticide.

Safety Tips When Using Hydrated Lime

Hydrated lime can irritate skin and eyes. Follow these precautions when handling:

• Wear gloves, long sleeves, goggles, mask, and boots when applying hydrated lime. Avoid direct contact with skin and eyes.

• Wet down lime before mixing to prevent breathing dust. Work in areas with good ventilation.

• Keep hydrated lime locked away from children and pets. Clearly label containers.

• If skin burning occurs, flush immediately with cool water for 15-20 minutes. Seek medical treatment for eye burns.

• Wash hands, arms, and clothing after working with hydrated lime, especially before eating or drinking.

By using proper protective gear and handling hydrated lime carefully, the risks of injury are minimized.

Storing Hydrated Lime

To maintain efficacy, store hydrated lime:

• In sealed plastic or glass containers in a dry location away from moisture.

• Away from acids, chemicals, and fertilizers to avoid unwanted reactions.

• Out of reach of children and pets in a locked cabinet or shelf.

• With a permanent label identifying it as hydrated lime. Include a warning about skin/eye damage.

• In a cool area without extreme temperature fluctuations.

Properly stored, hydrated lime will remain effective for 9-12 months before starting to break down chemically. Discard if it develops clumps or other signs of moisture damage.

Using good safety practices and application techniques, hydrated lime can be an effective pH adjuster for gardens. Understand its rapid action compared to standard ag lime when adding it to your soils.