There are many reasons potatoes have become such a ubiquitous part of both Australian and world cuisine; they taste great, they are enormously versatile and for a starchy tuber, they have a surprisingly balanced nutritional content, but most importantly of all they are surprisingly easy to grow. However, growing a potato patch in your garden isn't just a case of planting some tubers and waiting until harvesting season, and despite their hardiness, most potatoes will need a little boost from time to time to reach their full size and potential.
To that end, any potato farmer worth their salt will periodically add fertilisers to their potato patch, but not just any fertiliser will do. In fact, adding the wrong fertiliser can actually do more harm than good to your spuds, so to get the best from your crop, you should look out for potato fertilisers with the following key properties:
Many casual gardeners eschew organic fertilisers in favour of cheaper, more powerful synthetic fertilisers, but applying synthetic fertilisers to already-planted seed potatoes can damage their skins and leave them vulnerable to disease and burrowing insects. You can apply synthetic fertilisers to the soil before planting your seed potatoes, but they generally do not stick around in soil for long, and established patches should only be treated with organic fertilisers. Organic fertilisers containing bone meal, kelp meal and poultry guano are particularly beneficial for potatoes.
High (but not too high) nitrogen content
Nitrogen is an essential substance for healthy growth in almost all plants, and the humble spud is no exception. Fertilisers rich in nitrogen will promote the growth of both potato foliage and the tuber beneath, but this doesn't mean you should shovel as much of it into your soil as possible.
Generally speaking, potatoes need more nitrogen during the first half of their growing cycle than the second half, as it helps them to establish healthy foliage that can absorb light and promote tuber growth. Nitrogen levels should be lowered during later periods once the tubers are established, as too much nitrogen can cause potatoes to become oversized, spongy and vulnerable to blight and other infections.
Performing this delicate balancing act without help can be difficult, so many garden fertiliser suppliers sell potato fertilisers with different nitrogen contents for different times of year. You should also bear in mind that potatoes planted in drier, sandy soils will need more nitrogen than those planted in loamy soils, as water drainage takes a lot of the nitrogen content of sandy soils with it.
High phosphate content once tubers are established
Phosphate-rich fertilisers are particularly important for growing large, healthy potatoes, and every good potato fertiliser will contain significant amounts of phosphate salts. However, these phosphates are much more important for tuber growth than they are for foliage growth, and applying too much to young plants that have not yet established a tuber can cause damage, so the phosphate content of your fertiliser should be increased gradually using supplements as growth progresses.
To learn more about garden fertilisers, contact a company like Mirco Bros.