Pest Rescue Guide: How Outside Clones Brought Mildew, Mites & Thrips Into My Tent
A real battle log — how one batch of outside clones cost me a clean grow, and the rescue plan I ran to fight back.
Hi, I’m Dank Canna
I’m a grower from South Africa. I’m not really a “public figure” type — honestly I’d rather be in the tent with my plants than in front of a camera. But I’ve learned a lot the hard way, and if this saves you the headache it saved me, it was worth writing down.
My confession
For years I grew clean, straight from seed — no real drama, no bugs, no mould. Then I brought in some clones from outside… and around that time, life pulled me away from my grow for about four months. My sister stepped in and did her best to keep things going, and I tried to help over the phone — but let’s be honest, remote grow-support only goes so far.
By the time I got home, I walked straight into webbing. Spider mites had taken the place over, with mildew and thrips along for the ride. It’s amazing how fast a small problem becomes a full takeover when you’re not there every day to catch it.
The mistake nobody warns you about
Pests and disease don’t appear from nowhere — they hitch a ride. The fastest way to infect a clean grow is to bring in an outside clone. That one decision cost me mildew, spider mites and thrips.
That batch was the one and only time I brought in outside clones — and after what it cost me, it’s a big stop sign for me. I haven’t done it since. But if you do bring clones in, here’s the routine I follow now:
- Observe first. New plants stay separate and I watch them for about a week before they go anywhere near the grow room — you’d be surprised what shows up once you’re actually looking.
- Treat before they mix. I hit them with Ludwig’s first to knock out the pests — adults and young — so nothing rides in with them.
- Only then do they earn a spot in the room.
Know your enemy: spider mites
The tell-tale sign is fine sandy stippling — thousands of tiny pale speckles across the leaf, where the mites have been feeding. The first signs are fine stippling and tiny dark specks — this is where you want to catch them. Advanced infestation shows as silk webbing, mites and eggs living in it, which is what greeted me at home. Webbing means they’ve been breeding for a while. Catch the early stippling and you’re lucky — act fast either way.
My battle plan (IPM)
My rotation — what I actually used, switched around so the pests never adapt to one product: Bioneem, Ludwig’s, Margaret Roberts.
My main hitter is Ludwig’s, mixed strong at 25–30 ml per litre — the strong end of the recommended dose — in my sprayer. I give it 3–4 days, then hit them again, because you have to catch the next generation before it breeds. I rotate in Bioneem (neem-based) and Margaret Roberts organic so the pests never get a chance to adapt. Coverage is everything, especially the leaf undersides.
Between sprays I inspect every single day — naked eye first, then a microscope loupe (60–100x) to check the leaf undersides for live mites and eggs. That daily check is half the battle — it tells you if you’re actually winning.
The sequence I follow: two hits of Ludwig’s, 3–4 days apart, to knock down the adults and young. Then 2–3 days later I bring in Bioneem — my inhibitor, to break the breeding cycle. After that I switch to Margaret Roberts to maintain and stop them coming back. And if I still see fresh signs after all that? I seriously consider a full cull — sometimes cutting your losses saves the whole room.
Defoliation to aid recovery
Stripping damaged growth improved airflow and let the plants put their energy into recovery instead of feeding bugs. I go in properly — bottom leaves first, because that’s inevitably where mites start. Off come any fan leaves showing visible signs — stippling, or dark black spots. Then when I spray I drench them, gently rubbing the leaves as I go to knock the mites and eggs loose. Straight into the clean tent afterwards, and always lights off — wet leaves under the light will scorch.
Where it stands today
I’m not going to pretend the war is won — I’m right in the thick of it. The mites rode in on outside clones, so all my mothers went on the chopping block. My mothers are still lush and healthy, but I’m weighing up taking a round of clean clones off all three before I cull — to save the genetics. My seed line is safe either way.
Why start over from clones instead of saving the big mothers? Honestly? It’s far easier to win the pest war on a small clone than a big bushy mother. Fewer leaves means fewer places for mites and their eggs to hide — a clone is a clean, simple fresh start, while a mother in full veg is a jungle for insects to disappear into.
Take it further
This is the rescue plan. For the full library — strain guides, a feeding calculator, a health guide in your pocket and grow tracking — get GrowLegend, free on the App Store.
Stay Dank. — Dank Canna