Declaring plant spider mite free?

[CROrchid]

Some three months ago, I noticed some spider-mites webbing under the leafs of a Dendrobium nobile cane. Once I took a closer look, I could see them moving around...now, since I had more orchids around it and was not particularly attached to the said plant, I decided to dispose of it to prevent spread to my other plants. Anyway, the same day I discovered a few silky strings on the leaves of my young Phragmipediums and maybe 2 or 3 mites per plant. I soaked some kitchen towels with water and swiped all the leaves and crevices of the plants, repeated this for the next two weeks.

It's been some two months since I've swiped them the last time, I have been checking them once per week (by using a flashlight in a completely dark room to look for webs and small yellowish mites moving around) but was unable to find a single mite or silk thread on them. Is it safe to declare the plants spider-mite free?

Note: I keep the plants all year inside my apartment so the temps never go below ~20*C which means that mites should not go dormant.

[aliceinwl]

I think you’re safe. When I had my mite issues (also from a new Dendrobium nobile) I found going over the plants with a magnifying glass really helpful too. But, after two months, I’d expect to see some obvious mites if they’ve established.

[estación seca]

Spider mites may live on plants but populations might not explode. If you have other plants they almost certainly have a few. It's almost impossible to get rid of them completely, unless you get rid of all your plants, and don't replace them. The key is to keep watch and treat at the first sign.