Water and Fertilizer

Cashews grow best in sandy soils, but sandy soils don't hold much water and are generally not very fertile. The trees will still do fine without additional attention.

However, if a good crop is important to you (read: if you want to grow them commercially) then you need to supply your cashew trees with additional water and fertilizer. 

Irrigate during dry periods, and fertilize the trees when they actively grow, as well as during flowering and nut development. (They will mainly need nitrogen and phosphorus, and possibly zinc.)

Harvesting Cashews

Cashew trees flower and set fruit during the dry season (winter), and you should be able to pick them within a couple of months.

The fruit in the picture is ready to harvest. (As with all other fruit in my garden, a beak shaped hole is the sign that it needs picking, ready or not....)

If you don't have birds dictating your harvest times use these signs: the apple has a nice pink or red color (some are yellow) and the shell of the nut turns a dull grey. When the fruit falls to the ground it's definitely ready.

Separate the cashew apple from the nut, and enjoy the apple. Luckily the nuts keep very well inside their shells. You can store them for two years so you don't have to process every batch you pick. Keep them somewhere cool and dry until you have enough to justify the effort of processing them.

Cashew juice is poisonous when mix with milk or it can be risky to drink milk after eating cashew  fruit and therefore a period at least  two hours should be given after the eating cashew fruit or vice verse.

Processing Cashews

You can't just shell and eat cashew nuts like other nuts. Their shell is full of a horrible, caustic liquid that will burn holes into you!

The challenge is to separate the nut from the shell without getting the stuff on your skin, or worse, into your eyes.

One method is to freeze the shells, and then separate the shell from the nut before it thaws. 

You still need gloves and long clothes and I'd also use safety glasses, just in case. The nuts can be eaten raw, but please, please make sure they are not contaminated with any of that liquid!

The roasting method requires oil, and a clear mask and long gloves and sleeves and pants and an apron...

Heat the oil to 210°C and then drop the nuts into it for two minutes. No longer or they will become too brittle. Be careful when putting the nuts in because they will squirt that liquid at you as they hiss and jump in the oil...

When they are ready cool them in a bucket of water, get them out of the shell, and dry them. Yum. (Or so I'm told. I have to admit that I haven't tried that method yet...)

Another roasting method is to heat the nuts for a minute in an open pan with holes (so the caustic liquid can drain away). I think you are supposed to do that over an open fire. Don't breathe in the fumes, and if the nuts catch fire douse them with water... After the roasting you have to put the nuts into sawdust or something absorbent to remove the last of the caustic liquid.

After roasting and drying you can finally shell your cashew nuts.

Sounds interesting,isn't it?

Good luck, and don't despair if you end up with only a few edible nuts the first time around. I'm told it takes some practice. I should probably start practicing or I'll never learn it...