Lime is the most essential yet most neglected nutrient on Irish farms

Lime is an essential nutrient but is the most neglected nutrient on Irish farms.

Soil pH is also critical for maximising the availability of nutrients (N, P & K) applied in organic and chemical fertilisers.

Lime is continually being lost from the soil and needs to be replaced as part of a nutrient management programme.

Key facts

  • Drainage water can remove approximately 250 – 625kg/ha, depending on the soil type, of lime equivalent each year
  • Light free draining soils will lose lime more quickly than heavier soils
  • A crop of first cut grass silage 5t/ha DM) removes approximately 75 kg/ha of lime equivalent
  • A finished bullock removes approximately 25kg
  • 1,000 litres of milk removes approximately 3kg of lime.
  • 1,000 litres of milk removes approximately 3kg of lime
  • Nitrogen fertilizers also have an acidifying effect
  • Each 1 kg of N applied as CAN or Urea will generate acidity that will require approximately 2 kg of lime to neutralise

Over the last four decades, lime usage has declined from an average of 1.7 million tonnes in the 1980’s to an average of 725,000 tonnes in the 2000’s.

Today approximately 60% of mineral soils are below pH 6.0 with 25% of soils with a pH below 5.5.

The % of soil samples from dairy farms, analysed by Teagasc, with low soil pH, P and K from 2007 to 2014 Source: Teagasc
The % of soil samples from dairy farms, analysed by Teagasc, with low soil pH, P and
K from 2007 to 2014 Source: Teagasc

Soil test results indicate that 90% of soils have suboptimal fertility to maximise grass growth (target soil pH = 6.3, target soil P & K Index = 3)

Low soil fertility (e.g. soil P Index 1) equates to a loss of in excess of 1.5 t grass DM/ha per year, which is worth €300/ha per year


Growmax is a quick acting soil improver produced by Clogrennane Lime.

It is ideal for conacre or leased land as the fast reaction of the product means farmers see an immediate benefit.

Growmax is suitable for grassland and tillage. It is also easier to apply on wet and hilly land as smaller equipment is required.


It is a granular quicklime product with the following characteristics:

  • Total neutralising value of Growmax is 160-170 compared to 95-99 for granulated limestone
  • Rapidly raises soil pH, thus releasing valuable nutrients for plant uptake
  • Promotes microbial life which aids release of plant nutrients from animal and plant litter
  • Can significantly increase pH with a single application if required
  • Supplied in 375kg bags – 4 bags per 1.5t pallet

How Growmax is manufactured?

The Limestone is blasted in a quarry and then crushed to uniform size.

It is then burnt in the Kiln at 1000 degrees c for 15-20 hours the product produced from this process is called quicklime with a calcium content of 68%.

Total Neutralising Value (TNV) is a measure of the potential of a material to neutralise acid and in turn, raise pH.

growmax 3

Most granulated limestone products have a TNV of 95-98%, ground Limestone has available TNV of approx. 35%. Growmax has a TNV of 160-170%.

Trial results on the use of Growmax on farm showed a noticeable improvement in root structure and also an increase in yield of 1t/ha in spring barley .

Key tips for Growmax application

  1. After spreading allow minimum 14 days before grazing
  2. Allow 10 days – 2 weeks before spreading slurry
  3. Don’t spread Growmax when closing for silage
  4. Allow an interval of two months between spreading urea and lime
  5. Growmax can be spread all year around
  6. Best results if incorporated in seedbed in a tillage situation
  7. Best results in grassland if 24-48 hours of dry weather after spreading

Application rates

It is recommended that if a farmer has a low pH 5.5-6.0 farmers should spread 150kgs per acre cost €27. If a farmer has a pH close to 6.0  farmers should spread 75 kgs per acre at a cost of €13.50.

Not all of the product breaks down in year 1 approx 80%, according to the manufacturer.

Growmax is supplied in four 375kg bags – 1.5 ton per pallet and is available from your local Agricultural Merchants.