Growing Advice
Protea Soil Type Guide
Proteas have specific soil requirements, if the soil in your garden isn’t suitable for Proteas there are steps you can take to amend the soil. It is important to know what kind of soil you have in your garden to determine what steps you need to take to ensure your plant can thrive. Use this guide to find out your soil type and the steps you need to take to adjust your soil before planting your Proteas.
Soil Type
Soil Type
Soil Type describes the ratio of sand, silt and clay that a soil is composed of. The proportion of these particles gives soil different properties. A simple test you can perform to determine what kind of soil you have in your garden is to take a moist sample in you hand a squeeze it.
Clay Soil
Sandy Soil
Loamy Soil
Clay Soil
Clay Soil
Clay soil is generally heavy and is compact in nature. Due to this it is often difficult for plants to establish roots in clay soil. Heavy clay soils are not free draining and can easily become water logged. During dry weather, clay soils can also crack and can be very difficult to rewet. If you have a clay or heavy clay soil it will be necessary to improve it by digging in composted woodchip mulch and gypsum to break up any residual clay and improve drainage.
Sandy Soil
Sandy Soil
Sandy soils are at the opposite end of the scale to clay. They are open and very free draining. This can cause problems as water and nutrients pass through the soil before the plant has a chance to use them. Organic matter such as composted woodchips and leaves can be added to a sandy soil to help slow down the loss of water and nutrients and give plants a chance to absorb what they need.
Loamy Soil
Loamy Soil
Loamy soil is the dream of every gardener. It’s a mix of clay, silt and sand which results in a rich, dark and crumbly soil that is free draining but will retain moisture. If you have this kind of soil, you will not need to amend it before planting.
Soil pH
Soil pH
pH, which stands for potential of hydrogen, is the measure of acidity or alkalinity of soil. The pH scale is a numerical scale running from 1 to 14. A pH of 7 is neutral; anything less than 7 is acidic and anything higher than 7 is alkaline. The pH of a soil is essential in determining how well a plant will grow, as it influences the availability of nutrients. The ideal soil pH for most varieties of Proteas is 5 – 6, however they can tolerate pH slightly above or below this. The pH of your soil can be tested by purchasing a pH Test Kit from your local nursery or hardware store.
Acidic soils are recommended for Proteas because nutrients such as phosphorus are less available in this range, and they need far less phosphorus than other plants. Iron is also more available in soils with a pH below 6, which is important to maintain healthy green foliage.
If the pH of your soil is below 4.5, most of the important macronutrients become unavailable to your plant. You can raise the pH of the soil by applying calcium carbonate, which is sold as garden lime or agricultural lime at nurseries and garden centres.
If the pH of your soil is above 7, you can make it more acidic by adding elemental sulphur. It is a bit trickier to lower the pH than to raise it, as it may drift back to neutral or alkaline over time. You can apply a drench of iron sulphate to the rootzone of the plant to help lower the pH and give the plant a boost of iron if you notice the foliage turning yellow.
Fertilisers
Fertilisers
Fertilisers can be present at various levels depending on the soil type and the history of land use in your area. Soils with a higher content of clay will retain more nutrients than sandy soils. Nutrients like phosphorus bind to the soil and can be present in a garden for long periods of time if high-phosphorus fertilisers have been used. Therefore, it is best to avoid old garden beds that phosphorus has been historically applied in.