Taking a close look at your plants is often taken lightly. Most farmers with decent close up eyesight believe they can see everything they need to see. That isn’t always the case, particularly with pests and disease. Cannabis growers also have a need for some form of magnifying tool when determining when to harvest their plants.
Most pests (and their damage) can be seen with the naked eye, but identifying those pests is easier if you can scope them. Some pests are only visible with strong magnification however, like russet and broad mites. An infestation of these pests is usually identified by the damage to plants, but confirmation is only possible by spotting the eggs on the underside of the leaves. This requires a 100 power handheld microscope. Diligent growers will monitor their plants throughout the season so they can be proactive with treatments. The eggs will be apparent long before the mites reach population levels that start to cause damage.
One favorite style of scope is this 100x "Slim-Scope" by Grow 1,
The user can hold the scope and adjust the focus with one hand
while the other hand holds the subject.
Other pests like spider mites and aphids can be seen with the naked eye, but a magnification device is still useful to positively ID the bugs. Finally, legal cannabis growers need to monitor the color of their trichomes to make sure they harvest at the right time.
This common style of zoom microscope can be challenging
because the focus knob is hard to use unless you use two hands,
which makes it hard to secure the object you're trying to look at.
There are plenty of choices of magnifying tools. A simple magnifying glass can work for most tasks. Some prefer jeweler loupes. There are even scopes that can attach to your smart phone that allow you to take pictures. Some scopes offer a zoom feature. One thing all scopes that are available at your favorite grow store have in common is an illumination feature that lights up the subject.
This style of scope can attach to your smart phone to take pictures.
For spotting mite eggs, the 100 power scopes are necessary, and these come in two styles. There are 60-100x zoom styles, and a 100x fixed style. Smaller scopes like the zoom model can be hard to hold and adjust the focus, so a favorite is the white scope with split tubes that allows the user to hold the scope and focus with one hand while the other hand holds the subject in place.
Some people prefer a loupe. One handed operation and no need to focus simplifies the
process. Loupes do not magnify enough to see mite eggs, however.