Some kind of bud rot..

[theresab]

-Problem: I have some kind of bud rot. Maybe it is a mold but it isn't white or powdery, just brown. It seems to mainly affect the base of a bud, but one main cola is also affected at the top.
-Medium/grow method: soil
-Feed and supplements used: Nothing for most of the time, other than (very) occasional seaweed. For the last 2 weeks I have added BioBiz fish mix and BioGrow. First week 4ml each per plant and second week 2ml fish mix, 4 ml BioGrow.
-Water source: regular tap water.
-Strain and age: Magnum Buddha, at least 13 full weeks.
-Climate: normal UK climate. Normally lots of rain, average humidity 70-90%. Temperatures normally between 52-70 F. However, this summer over the last 4 weeks not a drop of rain until yesterday, and temperatures between 75-90 F. Humidity has dropped, to around 40-60%.
- Light used: sunlight
-Additional info: I'm growing in 60 litre cloth growbags. I grew in a greenhouse with decent air circulation for month of May and part of June (1st 6 weeks). After that the weather has been great and the plants have spent the last 8 weeks in the sunshine during the day (8am to 8pm) and in the greenhouse at night. Since there has been no rain I have been controlling all the watering. I am pretty sure I was overwatering, and my plants are small and not as far developed as I expected for auto flowers (although because it is an outdoor grow that also may contribute to their state of development). For the last two weeks I've been watering every other day. Symptoms appeared almost 2 weeks ago, two leaves close to the top of the main cola of my most mature plant started to brown. I pulled them out but took pics. This week another small leaf started to brown. Today the very top of the bud started to brown. I investigated further and saw that there was some brown rot underneath. I immediately looked for other areas. I found another on this plant and 3 smaller areas spots on the other plant. All were small side buds, except the issue on the main cola. Therefore I have cut the small buds and I am hoping I removed the whole of the problem at the top of the main cola.

--Pictures:
All plants last week. The two affected plants are the middle two.

First brown leaves:

Sadly I did not take pics with the buds on the plant, with the exception of the browning at the top of the main cola:

I was too concerned about getting it all off, and salvaging the untouched bits of bud that I cut as well as the rest of the plant. But I did take pics of the affected bits off the plant afterwards.

Any help to keep this from continuing is greatly appreciated.

 

[theresab]

Oh, here's a close up of the first bud I discovered after removing the good bits.

 

[theresab]

And I made a mistake, I am not feeding BioGrow, I'm feeding BioBloom.

 

[Waira]

yeah, that probably bud rot, aka botrytis,... nothing can be done except treat it like gangrene, which you have,.. you're at the mercy of the weather, and the plants are overly green still, making me think too much N was going in from what feeds were given and the soil,.. neither of which are nearly balanced and complete enough to get through blooming with stronger hardier plants,...
this mold is miserable shit, it travels inside the vascular system to new tissues, so outside treatment is basicallyout, plus you don;t want residues on the buds,... when you cut, you make new open wounds which doesn't help, but no work around there,.. just do it early in the day so it can dry out and seal some,.. treat open cuts with alcohol or peroxide with a Q-tip or something,...

 

[theresab]

o Great. Should I just wait for it to appear and dismantle the plant piece by piece, leaving it other parts to grow as long as possible? If these plants were healthy how long do you think they still have to go? I'm now on week 14 of an auto flower!

Should I stop feeding them what I've been feeding? There is so much information out there and due to a family emergency I was not able to care for these plants as I should. but I do have one other coming along, just started to flower last week.

What do you recommend I do with this one? Again that's just in potting soil and I've not fed it anything other than water. I'm assuming I should keep it away from the others. Is there anything else I can to do that one to help prevent this from happening?

Also is there anything I can do at this stage to prevent the other two plants from getting this? A gardener friend recommended that I no longer keep these in a greenhouse at night, just outside from now on. The weather is supposed to be dry (i.e. no rain) starting today and hot again by the end of this week for the unforseeable future.

 

[Waira]

..yeah sadly, that's all you can do,.. there's no "fix" for it short of bringing them into a controlled climate and getting the RH% low to reduce activity,.... your late feeds, and early lack of contributed to the susceptibility,... gotta have the right foods, right time- .. the poor budding is partly caused by too much N going in during bloom,... low bud:leaf ratio,...also make the mold go apeshit,... Worse, at 14 weeks, these are malfunctioning plants! They should have finished weeks ago,...
Cool humid nights, and/or low air movement are a bad scene, these trigger the spores to activate, so do what you can to minimize this; even a fan outside (I've done this and it really helped!),... spores are everywhere all the time, so treating a plant in early bloom is still OK, but after buds form up, treating becomes difficult to impossible,...