Lime sulfur before flower set, saves headaches later

Been doing this since the mid-80s and most people my age either forgot it or never knew it. Hit your plants with a diluted lime sulfur spray right as they start to stretch, before any bud sites form. Old orchard trick. Cuts down on botrytis pressure considerably when the humid weeks hit in late summer. Mix it weak. About 1.5 tablespoons per gallon. I do two applications, ten days apart. Stop well before you see pistils swelling up. You don't want any of that on developing flowers. Live in the Pacific Northwest. Run some big outdoor plants every year. Lost entire harvests to bud rot in the late 80s before i started doing this consistently. Haven't had a catastrophic loss since. Still get some spot rot in bad years but nothing that wipes you out. This works best if you're also managing your canopy. Dense growth in a wet climate is just asking for trouble regardless of what you spray. Lime sulfur buys you insurance, not miracles.

3 comments

3 Comments

Experienced9d ago

Solid reminder, and the timing point is the key thing people miss. Most folks who tried this and had problems pushed it too late into stretch and got that sulfur smell locked into early flower tissue. You can absolutely taste it if you're not careful, and i mean really taste it, like struck match, minerally weirdness that lingers through even a long cure. Ruins everything you worked for on the flavor end. The canopy management point deserves more weight than you gave it honestly. I run dense phenos sometimes, chasing specific terp profiles, and no spray in the world saves you if you've got a humidity trap built into the structure of the plant. I've had to make some hard cuts on keeper phenos just because their architecture was a death sentence outdoors in a wet year. Heartbreaking but you do it. One thing worth adding for people in the PNW specifically: if you're running any late-finishing strains, your window to stop applications gets really compressed. You might only get one clean spray instead of two before pistils show. Better one application timed right than two with the second one too close to flower set.

Experienced9d ago

This is solid for photoperiods but worth flagging for anyone running autos outdoors -- the timing window basically doesn't exist for you. By the time an auto is stretching it's already setting bud sites, sometimes simultaneously. I tried a diluted application on an outdoor auto last summer just to see and the stretch-to-pistil gap was maybe a week. Not enough runway. For autos in wet climates I've had better luck leaning hard into canopy management and picking genetics that finish faster before the bad weather rolls in. Botrytis resistance through timing rather than chemistry. Less romantic than a century-old orchard trick but it works with how autos actually grow. The advice here is genuinely good for anyone running photos with a real veg window though. Just didn't want someone to read this and try to adapt it to autos one-for-one.

Expert Grower9d ago

The point about autos is fair enough, but I'd push back slightly on writing off the chemistry entirely. Even a single application at the right moment, even if that window is narrow, is better than nothing when you're heading into a wet August. Canopy work helps but it doesn't change what the weather does.