The two can seem interchangeable, but in fact they do not do quite the same job…
Use horticultural fleece for warmth (and insect protection)
Horticultural fleece is designed primarily for keeping plants warm without blocking sunlight. This makes it an excellent option for those growing winter crops in colder parts of the country – you can simply lay the fleece over the top of plants, making sure it is secured down with stones, and it will help protect them from frost. It is a good option for winter lettuces, spinach and wild rocket as it’ll help them to grow faster.
Use mesh netting for insect & bird protection
Mesh netting is just brilliant for protecting brassicas from pigeons (all year round) and butterflies (during spring and summer!) as well as protecting crops from other tiny pests. It won’t, however, do much in terms of keeping plants warm over winter. We’d recommend using it to cover kale, cabbage greens, mustard leaves, pak choi and tatsoi, swede and turnips. You could also use it to cover carrots and parsnip to protect them from pests.