101 ways to deter of invading battalions of ants...

[Trinity]

I am astonished at the number of ants gathering together right now, planning to their aphid farm on my delicious crops!

Here are some tried and tested barrier suggestions:

Cinnamon
Whole cloves or ground and sprinkled
Chalk
Tee tree oil
Eucalyptus oil
Pepper

[contadino]

There's always the faithful chickens, who'll put a dent in the numbers of ants. However, they might do some damage to your veggies too.

[Andy Hamilton]

one trick that I learnt on here (and can never remember who posted it) is to put jam beside your crops where the aphids are. The ants instead of 'milking' the aphids for their sweet honeydew much prefer the jam, in fact they love the jam so much they think that the aphids are going to eat it and start to kill them.

It works so well I have started to do it every year.

[Millymollymandy]

4. Encourage green woodpeckers into your garden.

[the.fee.fairy]

Andy: do you put the jam in a jar? or just stick lumps of jam around the place?

[Trinity]

Sounds like an awesome idea Andy!
Please do tell more. I am going to try it before I contemplate finding a pet ant eater...