potato fertiliser

Looking at the ads for potato fertiliser is it really any better than slinging in a handful of growmore?

Good chance that giving spuds exactly the right blend of nutrients for them will make a bit of difference, but whether that is measurable compared to a balanced fertiliser is anyone's guess.

On the whole they look very expensive compared to Growmore though! 

Poundland both the same price for 0.75kg box. Growmore 7.0 7.0 7.0 Organic potato fertiliser 4:2.5:8

Ray

I've never used a specific potato fertilizer before but was going to try a little experiment this year. Five polypots with my normal compost mix and five with the mix plus potato fert. at the recommended application. Same variety of spud, same growing conditions, etc so I'll be comparing total yield to see if makes much difference.

I always use potato fertiliser as it's designed to have the right balance of nutrients, rather than a balanced general purpose one.

If growmore is applied at a rate to supply enough potash for potatoes there is too much nitrogen which grows big tops. The value of high potash fertilizers is less on clay soils which tend to be high in potash.

The other approach is to apply growmore at half rate and then add straight potash. Potash is available in two forms, muriate of potash and sulphate of potash. Sulphate is supposed to produce better quality potatoes but is more expensive.

Potash is the expensive nutrient out of NPK which is why potato fertilizers always cost more.

Potash is difficult to supply organically.

If growmore is applied at a rate to supply enough potash for potatoes there is too much nitrogen which grows big tops. The value of high potash fertilizers is less on clay soils which tend to be high in potash.

The other approach is to apply growmore at half rate and then add straight potash. Potash is available in two forms, muriate of potash and sulphate of potash. Sulphate is supposed to produce better quality potatoes but is more expensive.

Potash is the expensive nutrient out of NPK which is why potato fertilizers always cost more.

Potash is difficult to supply organically.

Useful though fairly small amounts of potash can be found in comfrey and seaweed and many people use feeds made from these. Wood ash too although its alkalinity is likely to cause scabbing on potatoes if overused.

Poundland both the same price for 0.75kg box. Growmore 7.0 7.0 7.0 Organic potato fertiliser 4:2.5:8

Ray

How much was it Ray?