Is this a potassium deficiency?

Hi all,

I hate to be the complete novice asking for help, but unfortunately I am.
This problem has developed over the last few days and I'm quite worried about it.

My setup is very low tech, a somewhat opaque greenhouse in the garden. The plant gets fed with tomato feed and watered once or twice a week as and when it looks like it needs it. Interestingly, the soil seems to stay damp for much longer than my other plants (tomatoes, chillies, etc) which are dry after 2 or 3 days now.

It's as low key as possible, and that's the best its gonna get. I had enough of a job getting the mrs to agree to that, the suggestion of lights and a grow room in the house would have been laughable. So if it's a problem like they're not getting enough light, then all I can do is pray for sun :\

I've tried to diagnose this myself and even after reading LOTS of info on here, I'm a bit ashamed to say I'm still not really sure. It looks like what people describe as a potassium deficiency but rather than go out and buy some products that could potentially add to the problem, I thought I'd come and ask you knowledgeable folk for help first; any advice gladly received.
Cheers.

So over the course of the week they've worsened. I've stepped up the nutrient feed to a 19-19-19, which they had a dose of on Sunday before I put them outside to see if it was fresh air that they're lacking. Evidently it seems not, now I'm not sure what to do; it's heart breaking to watch them wither like this after being relatively healthy for the best part of 8 weeks.

Is it a nutrient deficiency? or perhaps over watering?
Any advice very gladly received...

There are posts in the forums that provides pictures of various problems and their causes. Search for that and you might have an answer. Good luck

don't feed them for a weak or two and just water when needed, those leaves are burning IMO.. water when dry, but not bone dry "moist"

Get some perlite in that soil.

https://www.google.ca/search?num=10&hl=en&newwindow=1&site=imghp&tbm=isch&source=hp&biw=1600&bih=1040&q=perlite&oq=perlite&gs_l=img.3..0l10.1395.2240.0.2365.7.7.0.0.0.0.148.808.1j6.7.0...0.0...1ac.bWVLCPhAB9w

Looks like oxygen would have a tough time traveling through that.

Could be magnesium. Dissolve epsom in water, 5 grams in 4 liters. feed. See if it helps. cn

<add> They look starved for light. I recommend moving them or adding a supp. light.

Lights aint gonna happen, as much as I'd love to see them benefit from it. Totally dependant on the British weather (yeah, I know...)
I will try the Epsom salts though, thanks for that.

Should I repot them into fresh soil, mixing some perlite into it first? Or can you somehow mix it in with the plant still resident?
Thanks guys, your help is very much appreciated

SortedMate said:

Lights aint gonna happen, as much as I'd love to see them benefit from it. Totally dependant on the British weather (yeah, I know...)
I will try the Epsom salts though, thanks for that.

Should I repot them into fresh soil, mixing some perlite into it first? Or can you somehow mix it in with the plant still resident?
Thanks guys, your help is very much appreciated

Click to expand...

I don't think you can do it with the plant still resident. However if it were mine ... I'd work to stabilize its symptoms before adding the stress of repotting.

Be very careful of overwatering however ... that could be part of the problem. Let'm dry out a bit. If you're in a moist climate, that will take time.
Oh and when you do repot, consider trying a cloth pot, like the Smart Pot brand. Better root aeration. cn

Interesting, I've got some tomatoes in a cloth pot (a 60lt 'bag' pot) and they're absolutely massive, nearly as tall as me with stalks fatter than my thumb. I wish the ganja grew like that

I've also got one of those air pots, but haven't used it yet, was waiting for the plants to get bigger.... was......waiting..... lol

I've brought the plants indoors now, 2 in the conservatory and 1 on the kitchen window sill (that raised an eyebrow with her indoors). I've closed all the conservatory windows as well to try and raise up the temperature and lower the humidity. I re potted one of the ones in the conservatory into fresh soil which I only lightly pressed down (think I may have packed too much in last time). When I brought it out from its other pot I saw that the coir pellet that I planted it into was still very much in a solid form. It almost seems like it was strangling the (fairly small) root ball, so I very carefully broke it up a bit whilst trying not to damage the roots. It's now repotted in fresh dry soil, I'll see how it reacts before considering the other two which have been left as they were.

Thanks again.

Yah when the lower-value plant goes bbooooommm, and the higher-value one goes ~urk!~, it's downright annoying, esp. when the two are receiving basically the same care.
I don't know how wet and what kind your soil is, so I'm hesitant to make a rec that could do harm. But mj plants are noted Mg/K piglets. However yours look like they don't have much margin for enthusiastic doctoring, so I'm gonna think some good thoughts your way and hope you find "the trick" with these. cn

So with a mixture of luck and will the plants have survived and are beginning to look half way decent. Drying them out seemed to be half the solution, this stopped the problems from getting any worse. After a week of being indoors in the dry and warm the uk summer sun finally decided to make an appearance. So, after a few feeds on the boosted nute solution, with the addition of some epsom salts, they're now looking a lot better. Node spacing is a lot less in the tops lately, I've just topped the biggest one for the second time now.

Thanks a lot for the help guys

They need bigger containers dude!