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Citrus trees and water hardness/pH?

#1 · 14th September 2024, 10:59 am

Hi, I have been growing citrus (Lemon, Lime & Satsuma) for a few years now, but with a few problems, 
most of which I seem to have resolved.

There is one thing that is bugging me a little & that is watering.

I think I have the frequency of watering sorted but it is the type of water.

I am a farmer and get very busy during the summer and so have most of my pots, 
including the citrus, on automatic water timers for most of the summer, but not the winter.

We are on a private water supply & the water comes straight from a borehole out of the chalk & so is very hard. 
All the soil in this area is Ph 8 and so the water is also PH 8.

The citrus are in an ericaceous compost with added grit on the recommendation of my local garden centre manager.

In the winter months I water using rain water and in the summer when feeding I also use rainwater, they are fed using a citrus feed.

My question is this, do I need to include a little sequestered iron and/or Epsom salts insorparated into the surface of the 
compost to counter the water hardness or is the ericaceous compost and watering with rainwater on occasion good enough?

#2 · 18th September 2024, 10:00 am

Quote from Lee Garden Ninja on 18th September 2024, 10:00 am
Hi @chas159
Thanks for your question about the pH of water and whether certain plants, in particular citrus trees need additional treatments to absorb essential nutrients.
The quick answer is yes, they will; this is because the hardness and pH of water and soil will impact how many of the macro and micro nutrients the plants can absorb. This is why certain plans prefer acidic soil, cacifuges, and other alkaline soil, cacioles. Rather than adding the treatment to the water, I would apply mulch or compost, as you suggested. But only do this if you're noticing yellowing of the leaves of your citrus plants. Adding too much wastes resources and can leach out into the wider environment, which you don't want!
Let me give some more details on soil pH for other Ninjas so I can be comprehensive.
Soil pH plays a crucial role in determining how plants take up nutrients because it directly affects the availability of essential elements in the soil. The pH level, which measures how acidic or alkaline the soil is on a scale from 0 to 14, influences the chemical form of nutrients and their solubility. Plants absorb most nutrients in a specific chemical state, and the pH controls whether they are present in a form that plants can easily access or in a form that is locked up in the soil.
Low pH (Acidic)
In soils with a very low pH (highly acidic), essential nutrients like nitrogen, phosphorus, and potassium may become less available because they can bind with other elements, making them insoluble and, therefore, difficult for plants to absorb. For example, phosphorus tends to bond with iron and aluminium in acidic soils, forming compounds not easily taken up by plant roots. Additionally, highly acidic soils may cause harmful elements like aluminium and manganese to become more soluble and toxic to plants, stunting growth and damaging roots.
Rhododendrons
Blueberries
Conifers
High pH (Alkaline)
On the other hand, in soils with a high pH (alkaline soils), other essential nutrients such as iron, manganese, and zinc become less available, leading to nutrient deficiencies. For instance, iron chlorosis, where leaves turn yellow due to a lack of iron, is common in plants growing in alkaline soils. These micronutrients, vital for plant health, are rendered unavailable as they become trapped in forms that the plant’s roots cannot absorb.
Lavender (Lavandula)
Clematis
Lilac (Syringa vulgaris)
The ideal pH range for most plants falls between 6.0 and 7.0, where nutrients are in their most accessible forms and are available in balanced quantities. Outside of this range, certain nutrients either become deficient or toxic, causing poor plant health. Adjusting soil pH by adding lime to raise pH or sulfur to lower it can help optimize the nutrient uptake for specific plants, ensuring they thrive by having access to the nutrients they need.
I hope that helps. Let me know how you get on!
Lee Garden Ninja

Hi @chas159

Thanks for your question about the pH of water and whether certain plants, in particular citrus trees need additional treatments to absorb essential nutrients.

The quick answer is yes, they will; this is because the hardness and pH of water and soil will impact how many of the macro and micro nutrients the plants can absorb. This is why certain plans prefer acidic soil, cacifuges, and other alkaline soil, cacioles. Rather than adding the treatment to the water, I would apply mulch or compost, as you suggested. But only do this if you're noticing yellowing of the leaves of your citrus plants. Adding too much wastes resources and can leach out into the wider environment, which you don't want!

Let me give some more details on soil pH for other Ninjas so I can be comprehensive.

Soil pH plays a crucial role in determining how plants take up nutrients because it directly affects the availability of essential elements in the soil. The pH level, which measures how acidic or alkaline the soil is on a scale from 0 to 14, influences the chemical form of nutrients and their solubility. Plants absorb most nutrients in a specific chemical state, and the pH controls whether they are present in a form that plants can easily access or in a form that is locked up in the soil.

Low pH (Acidic)

In soils with a very low pH (highly acidic), essential nutrients like nitrogen, phosphorus, and potassium may become less available because they can bind with other elements, making them insoluble and, therefore, difficult for plants to absorb. For example, phosphorus tends to bond with iron and aluminium in acidic soils, forming compounds not easily taken up by plant roots. Additionally, highly acidic soils may cause harmful elements like aluminium and manganese to become more soluble and toxic to plants, stunting growth and damaging roots.

Rhododendrons
Blueberries
Conifers

High pH (Alkaline)

On the other hand, in soils with a high pH (alkaline soils), other essential nutrients such as iron, manganese, and zinc become less available, leading to nutrient deficiencies. For instance, iron chlorosis, where leaves turn yellow due to a lack of iron, is common in plants growing in alkaline soils. These micronutrients, vital for plant health, are rendered unavailable as they become trapped in forms that the plant’s roots cannot absorb.

Lavender (Lavandula)
Clematis
Lilac (Syringa vulgaris)

The ideal pH range for most plants falls between 6.0 and 7.0, where nutrients are in their most accessible forms and are available in balanced quantities. Outside of this range, certain nutrients either become deficient or toxic, causing poor plant health. Adjusting soil pH by adding lime to raise pH or sulfur to lower it can help optimize the nutrient uptake for specific plants, ensuring they thrive by having access to the nutrients they need.

I hope that helps. Let me know how you get on!

Lee Garden Ninja