Repeated issues 2 weeks before harvest

Hi all,

Thanks for such a great forum and for all the immensely helpful comments in the past. I face an issue that I can’t seem to get nailed down:

For the past 4 harvest, every time we reach roughly 3 weeks to 1 week before harvest, it seems something goes awry with my plants. Be it that they go from being dense to fluffy, be it that a spat of insects damage them, be it powdery mildew, bew it botrytis, be it burnt/dried leaves, and even just plain drying out and whithering of the plant.

I have grown three years, and grown along with the season (thus, mostly plant at the start of spring, harvest somewhere around autumn.

May last year I upgraded my greenhouse to allow me to darken the two different spaces inside it, thus allowing me some lights in the one (for vegging plants/mothers) and another space that could be used for flowering with 12/12 cycle enforced by thew darkening.

I had a few good harvests, but then an aphid and whitefly infestation hit me. It was absolutely overwhelming, to such an extent that I finally had no harvest for two month-cycles, and essentially restarted after sanitizing the entire place, the pots, the tools, everything.

Since then, I have experience multiple harvests that have “fallen apart” mere weeks to days before harvest.

I have a cycle set-up whereby I am able to initiate a harvest once a month. I have the mothers and the vegging plants under the lights, and move the vegged plants to the flowering area, where they remain for a little over two months. I manage the space in such a way that I can keep adding flowering plants as the harvested ones go.

As mentioned, multiple harvests in a row, now, I have had plants (basically the entire harvest" just sort of “giving up” weeks/days before harvest, with a result of no, or very poor buds.

What seems to happen most of the time is that the plants seem to become fluffy (where they were dense a few days prior) and then their sugar leaves start becoming yellow/brown, drying out. Soon, most of the bud also starts looking like this, and voila! you have no harvest.

I have, from time-to-time had plants that get botrytis, and I am able to recognize it, and remove those plants immeditately. This one understands and accepts may happen sometimes, BUT, this drying out does not resemble it at all. And any botrytis plants are immediately removed always and destroyed elsewhere.

I have had, and have seen powdery mildew also, and have a combination foliar spray that I use. The one has ampelomyees quisqualis (forgive me if I’m spelling incorrectly, the label is wet and all letters are not clear) and the other has trrichoderma spp. I used them on a group of plants that are just now swithcing from veg to flower, and it seems these products make no difference! I’ve followed up three weeks in a row, and the powdery mildew on these new flowering plants is just sitting there. Back to the point: I have had PM in the past, and previously battled it by making sure conditions don’t allow it to grow, or by wiping the leaves down with a damp paper cloth, or by removing the leaves or entirely removing and destroying the plant.

With all the above said, the pics I include are pics of the plants as they were on Friday, I think (maybe Thursday). I started flushing past Monday. Supposed to harvest next week Saturday. I’m going to move the harvest to tomorrow, simply to try to save what I can, because they seem to be on the same past as the past three harvests: 50gr of dried product (that looks shitty and seems grown poorly outdoor - never mind in a greenhouse) from 6 3ft plants!!! I normally got that much from ONE plant.

So, yeah, the thing that keeps happening is thus the apparent drying out of the sugar leaves, the dense-to-fluffy change in the bud, and finally even a possible total drying out/dying off of the plant.

Info on what I use and do:

I plant in 5 litre pots, I use Freedom Farms organic soil mix in which to plant. I normally take cuttings from the mothers and the grow the clones from there. Two weeks in the incubator, 4 - 6 weeks veg. 1 Week switching in the flowering area, then 2 months, once switched, to harvest. Flush 2 weeks before harvest.

I use Biobiz Grow in a ration of 3ml to 1 litre of water when feeding the plants (feed once a week). Obviously I ramp up to this after incubation. Starting with 1ml per litre, and each plant receiving 250ml of the water-gorw mix. Next week 2ml per litre, next week 3ml per litre and remain there as the water increments to 500ml over those weeks.

By the time I move them to flowering area, I increment Biobiz Flower also from 1ml to 3ml, along with the Grow, as their instructions indicate. By the second week in flowering the plants are normally up to 1l water.

The 3ml nutes I add are HALF the recommended dose. Been doing so and using this for the past 3/4 years, haven’t changed that. I did change the following: since moving from the yearly cycle to the 4-month cycle, I am using the smaller (5l) pots. I used to use 10l and even some 20l pots during the year-cycles, as the plants grew near on 2m tall. On this new cycle that started last year may, I moved them to the 5l on the recommendation fo the soil provider. Also, obviously, the plants don’t grow as large.

I did stop using EM Pro-Soil (live microbes for soil) and also stopped adding CalMag since my new cycles. My plants never show any deficiencies and the soil provider also confirmed that their soil is loaded to easily meet the needs of the plants over a 4 month period. I used to add Calmag and Pro-Soil once a month.

I water the plants 3 times per week (one of the three being a nute feed mix as described above, and one feed being a molasses-water mix for the flowering plants).

I have 8 fans in a 4m x 6m greenhouse (2.3m high). I also have two large fans (about 60cm size) acting as “extractor” fans at the top of one of the sides, for heat and air exchange. I have a 1m x 1m inlet on the opposite side to aid inn air intake. It is covered by netting to prevent insects entering.

The greenhouse plastic allows 80% light in, and I have covered the roof area with a shadecloth that prevents 40% sunlight. Thus it is very bright and very light inside, but the shadecloth is more about working against heat. I also have an air-conditioner running in the flowering area to attempt to keep the temps at the plant-canopy level below 30 C. With the yearly-cycle grows I did not have shadecloth or an aircon.

I think that covers everything you may need to know? If not, please, fire away with additional questions.

Here are the pics of the dried-out or drying-out plants:

Here are pics of the newly-flowering plants, with the stubborn mildew:

Thanks for any advice/input folks. As always, much appreciated.

White powder mold means you have insufficient air flow, or air circulation and too high of humidity.
The appearance of the plants definitely look like nutrient burn.