How to Tell If Your Weed Has Spider Mites

Written by Lorien Strydom
February 17th, 2026

You spot tiny specks on your cannabis leaves and need to know what you're dealing with.

Is it spider mites, a nutrient issue, or something else entirely?

Spider mite damage starts as tiny white or yellow stippling on leaf tops, caused by mites piercing cells to feed.

Advanced infestations produce fine silky webbing on leaves, stems, and buds.

This guide shows you three fast confirmation methods that work in minutes, explains why timing beats panic, and helps you understand what your options look like if mites show up during flower.

In a hurry? Jump to the 60-second confirmation check at the end.

Table of Contents

• What Spider Mite Damage Looks Like
• Mite Damage or Nutrient Deficiency
• Three Ways to Confirm Spider Mites
• Why Spider Mites Multiply So Fast
• Single Treatments Fail Because Eggs Survive
• Conditions That Invite Spider Mites
• Special Considerations for Flowering Plants
• What Unchecked Spider Mites Do to Your Plants
• How to Verify Clean Cannabis When You Buy
• Your 60 Second Spider Mite Check

What Spider Mite Damage Looks Like

Early damage appears as tiny white or yellow stippling on the top surfaces of leaves.

These pinpoint dots show where mites punctured cells to feed on plant sap.

The spots start scattered and random, clustering more heavily where conditions are warmest and air movement is weak.

Older growth typically shows damage first.

Advanced infestations produce fine silky webbing on leaves, stems, and buds.

This webbing collects dust and looks dirty, distinguishing it from a single stray spider strand that might cross a plant.

The webbing becomes denser as populations explode.

In severe cases, entire plants can appear wrapped in dusty, grayish silk.

Heavily damaged leaves take on a bronzed or bleached appearance as chlorophyll destruction spreads.

Leaves eventually curl, dry, and die.

Mite Damage or Nutrient Deficiency

Early spider mite damage looks almost identical to calcium or magnesium deficiency, which causes growers to waste a week treating the wrong problem.

Mite damage shows random pinpoint dots with mites or eggs on the underside.

Calcium or magnesium deficiency shows interveinal chlorosis with no moving specks.

Check the undersides of affected leaves carefully.

Mite stippling comes with visible evidence underneath the leaf: tiny moving dots, translucent eggs clustered along veins, or cast skins left behind after molting.

Nutrient deficiencies follow predictable patterns.

Calcium issues typically show up as necrotic spots on leaf margins and tips, while magnesium problems create yellowing between veins on older leaves.

Neither nutrient issue will have moving specks, eggs, or silk present when you inspect closely.

Three Ways to Confirm Spider Mites

Flip the leaf and inspect the underside with a 30x to 60x loupe.

Shake a branch over white paper and watch for moving specks.

Rub the leaf underside and check for red or brown streaks.

Mites congregate on leaf undersides where humidity is higher and they're protected from direct light.

Most growers who miss early infestations never looked where mites actually live.

Naked-eye confirmation is difficult until populations are large.

The three verification methods below catch infestations early.

Loupe or Pocket Microscope

Use 30x to 60x magnification to inspect leaf undersides.

This range shows enough detail to identify mites, eggs, and cast skins without requiring expensive equipment.

Adults appear as tiny eight-legged specks, usually red, orange, or green depending on what they've been eating.

They move slowly but visibly at this magnification.

Eggs look like translucent spheres clustered along leaf veins.

They're often more numerous than adults since females lay dozens throughout their lives.

Cast skins appear as pale, empty shells where mites molted.

Their presence confirms active feeding and reproduction.

White Paper Test

Hold white paper under a suspected branch and shake gently.

Watch the paper for tiny moving specks.

Mites that fall onto white paper become immediately visible as they crawl.

Dust or debris stays still, making this test quick and definitive.

This method requires no gear and gives a fast yes or no when you need to confirm suspicions immediately.

Smear Test

Rub your finger across the underside of a damaged leaf.

Check for reddish or brown streaks from crushed mites.

This method works best as supporting evidence rather than primary confirmation.

Some plant pigments can create false positives.

Combine smear results with other confirmation methods for reliable diagnosis.

Why Spider Mites Multiply So Fast

In warm, dry conditions, spider mites complete their full life cycle in about one week.

This explains why populations explode before growers notice.

The cycle progresses through five stages: egg, larva, protonymph, deutonymph, and adult.

Each stage beyond egg requires a blood meal from your plants.

Females begin laying eggs within days of reaching adulthood.

A single female produces dozens of eggs throughout her short life.

Warm temperatures between 80 and 90 degrees speed development dramatically.

Cool conditions can stretch the cycle to several weeks, slowing population growth.

Two-spotted spider mites develop resistance to treatments quickly.

Growers call them the borg for their ability to adapt and overwhelm defenses.

Single Treatments Fail Because Eggs Survive

Most sprays do not kill eggs, so a single application will not solve the problem.

Eggs hatch days after treatment, restarting the infestation cycle.

Follow-up checks and applications every two to three days align with hatch windows.

This timing interrupts the cycle before new adults reach reproductive age.

Three to four applications spaced properly typically break the breeding cycle.

Missing follow-ups allows survivors to rebuild populations rapidly.

Understanding this timing explains why one spray and done always fails.

The biology demands persistence.

Conditions That Invite Spider Mites

Hot, dry, stagnant air accelerates reproduction.

Lowering temperature slightly, raising humidity moderately, and adding airflow slows them down.

Temperature drops of just a few degrees can double the time between generations.

This buys crucial time for treatment and prevention measures to work.

Humidity between 40 and 60% creates less favorable conditions for mites while staying safe for cannabis.

Levels above 60% during flower risk mold.

Air circulation disrupts mite movement and makes leaf surfaces less hospitable.

Gentle constant airflow beats occasional strong gusts.

Quarantine new clones for at least a week before introducing them to your grow space.

Inspect thoroughly with magnification during quarantine.

Change clothes before entering grow areas if you've been around other cannabis plants.

Mites hitchhike on fabric easily.

Keep pets out of grow rooms.

They carry mites from outdoor plants on their fur.

Avoid heavy nitrogen feeding that makes plants more attractive to mites.

Lush, dark green growth draws pests.

Special Considerations for Flowering Plants

If your plants are flowering, read this section before choosing any treatment.

Once buds form, treatment options narrow because residues contaminate product and strong odors cling to flower.

Anything sprayed on buds affects what you'll eventually consume.

Physical removal and careful water knockdown become primary tools during flower.

Manual removal of heavily infested leaves reduces populations without chemical residues.

Water sprays must reach leaf undersides where mites hide.

Thorough coverage matters more than spray pressure.

Light damage on flowering plants can be managed through the harvest.

Severe infestations that web buds may make plants unsalvageable.

Catching mites before flower preserves choices.

This reality should shape your inspection schedule and prevention efforts in future grows.

What Unchecked Spider Mites Do to Your Plants

Mites destroy chlorophyll and reduce photosynthesis.

Plants can't produce energy efficiently, stunting growth and development.

Yield drops significantly as plants divert resources to damaged tissue repair.

Potency suffers when plants stress and redirect cannabinoid production.

Heavily infested plants may not recover.

When webbing covers most foliage or buds show extensive damage, starting fresh often makes more sense than fighting a losing battle.

Assess realistically whether treatment time and resources will produce usable results.

Sometimes cutting losses protects your next grow.

The health effects of consuming mite-affected cannabis are unstudied and currently unknown.

Prevention during cultivation remains the goal.

How to Verify Clean Cannabis When You Buy

Reputable sellers publish Certificates of Analysis that screen for pesticides, mold, and contaminants.

These documents verify product safety through independent laboratory testing.

Mood offers millions of users hemp-derived THC, which is 100% legal and fully compliant cannabis.

You may have heard that the legality of hemp-derived THC is currently under attack, which could threaten the wellness of so many.

Read here to learn how to join the fight, and help us keep hemp cannabis accessible to all for a long time to come.

Mood works with pesticide-free partners and posts third-party COAs for every product.

This transparency helps buyers verify clean flower without growing it themselves.

Check that COAs include pesticide panels testing dozens of agricultural chemicals.

Missing categories signal corner-cutting regardless of branding.

Third-party testing from accredited laboratories provides independent verification.

In-house testing alone doesn't offer the same accountability.

Your 60 Second Spider Mite Check

Flip leaves and check undersides for tiny moving dots, translucent eggs, or cast skins.

Use a 30x to 60x loupe for clear visibility.

Run the paper test by shaking a branch over white paper and watching for movement.

Try the finger smear on leaf undersides and check for reddish or brown streaks.

Remember that follow-up every two to three days matters if mites are confirmed.

Timing beats panic.

Review the visual progression if you need a reminder of what early versus advanced damage looks like.

Consider light prevention tweaks going forward: moderate temperature and humidity, add airflow, quarantine new plants, and keep grow spaces isolated from outside sources.

Early detection preserves options.

Weekly inspections with magnification catch problems before webbing appears and choices narrow.