huerto = vegetable garden jardín = garden

"Huerto" is for grown something (as potatoes, tomatoes, leituge...) and "jardín" is more decorative, you can have a house with "jardín", in the "jardín" maybe you have barbacue or swimmingpool, some flowers...

Huerto is more like an orchard. Jardin is like our "garden." I am not a native speaker of Spanish so hopefully someone will confirm any other differences.