PH Dropping quickly?

[MisterE]

I'm sorry to post this question, I tried to search but the term "PH" is too short for the boards search function...

I'm having to PH Up my nutes more frequently as my plants grow. I'm wondering if this is considered normal, or if it is indicitive of any actual problems etc.

I only use 8 to 10 gallons or so total (going to change it out and measure carefully today) and the plants are only about 10 inches tall, on their 8th node.

I calibrated my continuous meter yesterday, and PH Up'd to 5.8, this morning it was 5.3 so I upped it back to 6.0 (couple drops too many, oops) and it's down to 5.9 already, only 2 hours later.

Any input on PH dropping appreciated, thanks.

[Weedhound]

Don't know Mr E, mine usually goes up as the plants get bigger. Only time i've had ph probs too low was when using new medium that I didn't rinse super well. You use RO water right?

[MisterE]

Yes I use RO water, some calmag as recommended (a little less than 5ml/gal actually), and weak gh 3 part nutrients. 5ml each per gallon currently.

I recently added a 400wMH and my water temp has gone up too high, does that create a PH issue?

My plan already for today is to drain the system, relocate my res to a new location which I've tested as several degrees cooler. But I dont know if thats related to ph. I also planned to go to latewoods feeding schedule which will be somewhat stronger nutrients.

[MisterE]

I'm also still dealing with the brown spotted leaf issue which I'd hoped had been corrected but it's still showing up. Red stems also. I know these could be related to nutrient lockout due to HIGH PH, but what about low? Yargh too many questions.

[Weedhound]

There is a range for ph...I believe it is 5.5 to about 6.2 but I'm sure others know better....anything outside the range will cause nute lockout......I'm sure 5.3 is dropping too low...no clues why it would be dropping like that.....sorry....

[Weedhound]

I would try the stronger nutes--latewood's formula too if you have run the other gamut--and it sure sounds like you have. I actually plan to try it myself next grow....i did have problems at one point not using ENOUGH nutes...can't remember if I told you about it......age...senility.....good luck

[MisterE]

Thanks, Weedhound. Yeah I have the chart for the various nutrients and their proper ph ranges etc. and have been keeping it at 5.8 as perfectly as I can. This rapid dropping thing is a new one.

It's at 5.7 now.

When I rearrange my room this evening, I'll raise up my grow tub a few inches so the system will hold overall a bit more water. Should make it more stable in general, and keep water temps cooler too.

Despite it all, the plants are doing well, crowding each other, showing pre-flowers and starting to give me a nice smell :)

[MisterE]

Well for anyone following along, I've rearranged my room to place my res in a cool corner compared to the hot spot it was at (my water temp would start around 68 degrees and climb to over 75 through the day, and I didnt like that). The temp at the ground level next to the res is 68 degrees. Looks like the right spot.

I raised my growtup up on 2 old phonebooks that were slated for recycling. Procrastination pays off! This allowed me to add about 2 more gallons total to my system, which should also help keep numbers more stable for longer, and temps lower. The exact volume is now 10 gallons. Perfect easy number!

I took a plastic straw and put it straight down into my res, and marked the waterline with a rubberband so now I can check water level very simply.

Based on my water volume and using the "latewood formula", I've come up with these numbers for Vegetative growth:

NUTES*: 10 gallon@8ml/gal = 80ml (1/4 cup + 1.44 tblsp)
*this is for EACH of GH 3 part. Flora, Micro and Bloom.

CALMAG+: 10 gallon@3ml/gal = 30ml (2.08 tblsp)

I've released my attic hatch which allows the warm air to vent naturally, and the ambient room temperature at the canopy top is now at 77 degrees. 400watt lamp is about 14 inches above canopy, and I have cool white flourescent shoplight as side lighting.

As to the PH, it's currently at 6.0 with the plain RO water. I'll nute and supplement it in the morning with the exact numbers above and monitor through the day. PPM is currently at 20.

If any of this sounds wrong or anything, let me know.

Thanks for watching! hehe :pimp:

[Weedhound]

I'll be interested to see what it is in the am before you add nutes etc...

[MisterE]

Hi Weedhound, this morning the ph was still at exactly 6.0, and ppm still at 20.

I've added the 3 part nutrients to my res a few minutes ago, and after an hour or so it should be fully circulated in my system.

After adding nutes, the PH dropped to 4.8. I know I'll need to PH Up it after it's fully circulated. We'll see just how much later on.

[Weedhound]

Mine always drops when I first add nutes too and I have to adjust up. Will be keeping an eye out for updates...

[xcrispi]

damn mr.E ,
i was always in a constant fight to keep ph from rising not dropping . i don't have the luxury of r/o water tho . no clue w/ this 1 .
peace
crispi

[MisterE]

Yeah that was strange. Maybe it was due to some rapid growth, or heck if I know.. RO water is nice. cheaphydroponics.com sells filters now. You just need a faucet adapter (can get one anywhere, same as a waterbed hose adapter)

At the moment, I've PH Up'd to 5.8 and it's stable for now. It took a few ml to get there. My PPM is at 1400, which is the highest by far it's ever been. Maybe I've been underfeeding them. I have been very light on nutes for fear of doing harm.

These are the reasons I started with the freebie seeds and not the "good" ones.

We'll see how it goes.

[xcrispi]

mr.E ,
yep joe at cheaphydro has shown me some real love . i get quite a bit there that i can't find locally .
crispi

[Weedhound]

odd, odd...keep us updated....keep an eye for overfert if you are jumping up numbers quick....damn numbers (actually I love them.....hydro.....right x?)

[MisterE]

Yes I am keeping a close eye.. The newest leaves are more light green and I'm afraid they're droopy. They also feel somewhat stiff. This is a sign of N overfert?
Good god this is picky stuff.
I'm going to let it go overnight at least and try to note any growth or changes carefully.

[Weedhound]

N overfert usually shows as a beautiful dark dark green in the plant which I have done personally.....the only other fert probs I had were 1. not using enough Cal Mag which caused some sort of MG def or something.....leaves were green but veins were yellow....stopped right away when I went to 50% Cal Mag with my nutes as suggested by my hydro guy (he told me to use 50 and 50 Cal Mag and nutes until I got to the top of the Cal Mag scale which I really havent' done yet...I use that all the way through flower) and when I went too low on the nutes...caused an iron def or something....the whole plant wilted down in about 24 hrs but came back w/higher nute level. None of these sound like your problem however.

keep us in the know....

[latewood]

Wow...My 3-part buffers right to 5.8-5.9 with ro water...Did you mess witht the calibiration on your pen? Using 3-part and calmag with rowater...You shouldn't have any problems like that, and NO...the temps don't affect ph, as far as I know.
I'll look in later. yellow is usually too low salts, but if you are following my recipe, then there is no way you are nute deficient or toxic...I can promise you that!

[MisterE]

Hi latewood. No I calibrated it just before this res change in fact. I'm extremely careful with that and it was perfect 4.0 and 7.0 when I was done. Plus the plain RO water was dead on 6.0 all night until morning when I nuted.

Could the fact that I used rapid rooters directly in the hydroton make any difference? I never added any water to them from the get go, as they lived up to their name. I've not noticed any material in the res either.

I make a point to shake the bottles well before adding the nutes also, and I add them micro, gro, bloom in that order directly to the res and stir each before the other (plus my water pump in the res stirs constantly and streams into the grow tub).

Since the change and adding the ph up, it's been pretty steady at 5.8. I havent had to readjust it at all.

The plants looked better (and smelled more) this morning. Last night 5 minutes before lights out, I very lightly misted the tops with straight RO water.

What about the old empty milk gallon jugs I use to store water? I rinse them and wash the hell out of them and rinse several more times and let air dry before using them for RO water. Is that a huge issue? I've never seen it mentioned, but trying to cover everything. My filter is close enough to the res where I could actually fill it directly that way, but it'd take several hours.

These issues all started before I started using your formula, so I'm sure it's nothing to do with that. The branch growth is great on these things, especially since they're so squat. Odd though that the shop I got the seeds says this strain likes to grow super tall. I think most of these things have to do with my inexperience with hydro, and starting them with my hard as nails tap water.

[scubajoe26]

Help.. Im having problems with my ph dropping while in the trays. The reservoir is at 5.8 and when I measure in the tray durring watering it reads 3.6 also have yellowing leaves and stunted growth. Doing ebb flow and RO water, water temp 78 degrees. Tray just cleaned 2 weeks ago.

[latewood]

Mister E In answer to milkjugs...check water ph before, and a day after put into jugs...you tell us...Is the ph different?

I don't know what would cause the rez to read 5.8, and then 3.6 in tray???

[Weedhound]

keep us updated Mr E!!

[MisterE]

Ok I'll try to update.

The PH of the plain RO water is 6.0 all around. So I'd say my containers are clean and neutral and not affecting PH since I fill them all week long at various times, then into the fridge until needed.

My PH since the res change has stayed at 5.8 since I adjusted it up after adding nutrients.

Since then, I've decided most of my new issues (stiff feeling, downward curving new growth, burned tips) were due to too strong nutrients. My plants may be too young for such a strong (1400+ppm) mixture. So I dipped a clean bucket in and removed about 2 gallons, and replaced with 2 gallons of plain RO water. PPM is now at 1110.

I also took a closer peek inside my grow tub and I decided some of the curl could have been due to "overwatering" maybe? I raised up my growtub another inch and a half or so.. Allowing me to keep the same capacity, just a bit lower water level.

The new growth seems more consistent now, and is not curling down. The branch growth is still very good, one decided to be a triple noded branch. Fine by me, lol.

I *still* have the issue of brown spots (yellowish in the center with a distinct darker brown/rusty border). Spots begin near tips and work their way inwards towards the stem basically. A few leaves have crisped right up. Mid level large fan leaves.

Incidently, if I started again today I'd leave only 1 plant per 10 gallon tub. There's simply not enough room between the plants unless you train them away from each other immediately. Clearly, 5 gallon buckets are the way to go with DWC unless you're going to be training your plants with a firm hand.

[Racerx]

I have a much harder time keeping pH consistent with RO water then with water out of the tap. With 18-20 gallon bubblers, I have to adjust pH down every day. The larger the reservoir, the less it needs to be pHed. This is one of the reasons I went with a large recirculating dwc settup. Complicated to setup, theoretically easy to maintain.

PS. Having grown 2 to 4 plants per 20 gallon containers I will never put more then 2 per 20 gallon container and I will train them away from eachother. DWC has explosive growth. I was given a 4 plant 20 gallon bubbler and it was a dissaster, even after flowering immediatly from clone.

[MisterE]

Yeah, I also made a recirculating system. Water pump in the res, 1/4" line to the grow tub streaming water 24 hours. It's the only way to be sure everything stays moving.

Mine is just miniature compared to yours. 18 gallon res, 10 gallon grow, 10 gallons total water. 1 airstone in the res, and 1 airstone beneath each plant.

RO water has no PH buffers, so it takes only tiny drops to adjust up/down, but it potentially fluctuates more up/down by the same token. Think so anyway.

[MisterE]

Well, after 6 days my PH is back to dropping about a 10th of a point per day. Adjust to 5.8 in the morning, and down to 5.7 by evening. I guess it's my system telling me that it wants to be fully changed every week.

[Alaric]

in water culture-------best solution I've found is to elimanate mediums. Yes Virginia ------it ain"t needed. Just another varabile to deal with.

I start at 5.2 and let it drift upward to 6.2-------look at the charts for macro/micro consumption of elements and it makes $ and cents to me.

This is the hbydro board board????????

Alaric

[MisterE]

Yes, I'm using a hydro setup. I started the seeds in rapid rooters and placed them in clean hydroton. I use RO water and GH 3 part, some CalMag+ and my PH doesnt rise, it falls.
Since I started using RO water, I've only hd to use the PH Up. Never the Down.

[Weedhound]

That is odd to me Mr E, I do the RR thing too, then into higromite and I can honestly say I've never had to use the ph up unless I've used too much ph down. Wish I knew what to tell you.....

[MisterE]

I'm....... magic! Thats it! ;)

I'm not too concerned I guess. Maybe at the next change in a few days, I'll pull out my water pump and tubing and run it in a weak bleach solution in case I have some funk in there. Res. doesnt smell bad, but it's not too much trouble I guess.

I'm also changing my MH to my HPS this weekend and going to flower (digital ballast makes it easy as a bulb change). If I dont, they're going to be taller than me when they finish, and I can't deal with that. They're still nice and bushy and have been showing pre-flowers for a while now. So I think it's time, come what may.

Also going to order the vaportek 4000 instead of a noisy carbon scrubber setup and we'll see how that goes.

[latewood]

I have a much harder time keeping pH consistent with RO water then with water out of the tap. With 18-20 gallon bubblers, I have to adjust pH down every day. The larger the reservoir, the less it needs to be pHed. This is one of the reasons I went with a large recirculating dwc settup. Complicated to setup, theoretically easy to maintain.

PS. Having grown 2 to 4 plants per 20 gallon containers I will never put more then 2 per 20 gallon container and I will train them away from eachother. DWC has explosive growth. I was given a 4 plant 20 gallon bubbler and it was a dissaster, even after flowering immediatly from clone.then you have other issues...the easiest way to have a consistant ph level is using ro water. Now I don't know what nutes you are using, but It is a lot harder to have consistant ph with tap watrer due to impurities and metals squewing the ratio's, and causing reaction's that in turn change the ph

I have absolutely no ph problems at all in drip, or dwc or any method using ro water. Now I use 3-part...and always will, So I cannot say about other nute formulas:smokin:

[MisterE]

Well, last evening my PH was reading 5.8 and this morning it was 5.1. Seriously, can someone explain to me ANY reasons why the PH in water drops? Whether it pertains to hydroponics or not, I'd love to hear it.

I spent some time peeking ever so carefully into my grow tub to see if I could spot any light leaks for example (even though from what I've read if I had algae, it'd create rising ph). I patched up a couple of pinhole light leaks. Nothing much else to report though.

I've tried searching the board as I mentioned, but the search function wont work on "ph" because search terms need to be at least 3 characters, lol.

[xcrispi]

hey mr. E ,
did you wash the hell outa your hydroton before you used it ?
crispi

[MisterE]

Yes, even though it was brand new hydroton, I rinsed and scrubbed and rinsed again before I used it. It hasnt done this forever, it started some time after I got my water filter strangly enough. The water goes in at 6.0 on the dot, 10 PPM or so, and if left alone it'll drop to 5 (a 10 fold difference!) within a few days if I dont use PH Up.

Would salt buildups cause drop in PH? Would anything sickness in the plant cause it? Bacterias? Molds? Fungi? Anything? I feel like I'm not seeing the forest for the trees so to speak, and it could be simple.

I'm ordering up a gallon of florakleen in the next day or so I think, but I sure wish I knew of any specific causes. With my luck I'll run it in there and it'll recur anyway.

Remember, my plants have also been showing what LOOKS like calcium or magnesium deficiencies for a long time, and thats never gone away. Now I've read that root rot can appear in the leaves similar to a nutrient difficiency, but would it cause the PH to drop? That seems backwards. They also dont look bad or smell bad.

Well I still have some hair I havent pulled out yet, so thats a blessing :) Plus both plants have definitive female pre-flowers on them which is good too.

[Flower Child]

Ec goes up, PH goes down=plants require less nutes.
Ec goes down, PH goes up=Plants require more nutes
Ec stable, PH goes up=Equilibrium=Good thang.
FC

[MisterE]

Thanks, Flower Child.

If it's that simple, I'm surprised I havent seen it before, but I dont know of many resource sites to look up information frankly.

So theoretically, after some number of days on plain RO water like I have been for a few days now, I should see PH stabalize, then turn towards rising. I'll keep an eye on it. At the first hint of rising, I'll consider a weaker diet for them.

[Weedhound]

I never knew that!

[MisterE]

Well, been 5 days now on nothing but RO water and the PH is still dropping a few tenths per day. Initially I added about 30ml of H2O2 to the res (10 gallon full capacity), and only PH Up since then. PPM is 30. I've needed to add 5ml of PH Up per day, approximately. Been topping up with plain RO water as needed.

Plants are growing, but I'm still kind of amazed that the only reason I've seen posted for PH to drop is too much nutes and nothing else. I can't even find another post anywhere here with a "ph dropping" issue.

Maybe I should just run half RO and half tap water, to make use of the PH buffers in the tap water? Or maybe 1 gallon out of 10? Any input on that idea appreciated as well.

[Weedhound]

Do you have a way to check EC? I do on my meter but I never really use it...always go with the ppms....I have actually had 2 of my 8 today come up with a lower ph but Im wondering if perhaps I used too much ph down yesterday.....obviously that wouldn't be your problem...just babbling....if I see it again I will check EC on my plants. I'm not sure that there ARE buffers in tap water.....just shades of either acid or alkaline with no stabilizers. Or perhaps more than shades......

[MisterE]

Hi Weedhound. No I only have a TDS meter, but isn't it just math to determine Ec?

I believe most tap water has ph buffers. Also, before I had my RO filter and used only tap water, the ph was always high and it took quite a bit more ph down to bring it down. With RO water, it'd only take 2 drops where it used to take 10mls. Thats the buffering capacity in action.

I did some reading on icmag forums, and there is a nice thread about water including PH and buffering capacities and such and such. If I add sodium bicarbonate (NaHCO3), (baking soda! lol) it should increase the buffering capacity without increasing the waters hardness. But I'm leary of trying it, and leaning more towards simply including some of my higher ph tap water first.

I peeked at my roots today and noticed some roots heading into my drain pipe. I gently fished out about a foot long group of roots, lol. I had visions of waking up one fine morning and my entire room is flooded, circuits blown etc etc. Gonna have to rig a barrier that blocks roots, but allows water to flow freely... yikes.

[Weedhound]

You could be right Mr E, my water is well water so there is probably a big difference between that and tap water....you could add an entire bottle of ph down and it would only hold it for a day or two before crawling back up....
I do find that when I first do a res change it takes, as you say, very little but does not stay very stable for the first day or so until I have added more ph down etc, then it seems to stay pretty much where I put it about 48 hours in. Now flowering is a different story with the ph probs

I use baking soda as ph up usually as I only have to use small amounts and it's easier than ph up for me....I doubt I would use it if I had to raise the ph a few points or so....or have to use it often but I have not had any problems using it so far....keep it on hand with my other crowd of bottles. I have found it raises ph kind of slowly over a few minutes so I add a little and then check it a few mins later because the number seems to rise a little more after a min or two. I don't seem to have that particular situation when using ph up/down so just a a heads up.

[MisterE]

Well also, the nutes have ph buffers in them, so theoretically a nute solution SHOULD hold it's ph level more stable than plain RO water (or any low ppm water).

Baking soda not only raises ph, it supposedly also has a buffering effect. So it COULD be a possible better choice for me (or supplement) since my RO water seems to be very very unstable.

I had to PH Up my res twice today in fact, and "chasing ph" is suppose to be bad for the plants. After the second dosing, I added about a quart of tap water and the ph rose a couple of more tenths to 6.2. That was 2.5 hours ago and I'm currently looking at 5.9.

Kinda driving me nuts obviously. I have 6 or 7 gallons of plain water on hand, so I may go ahead and mix up a batch of bloom nutes later tonight/tomorrow morning and do a quick drain and fill of the system again. Using some tap water as well.

I've got to get these blooming, they're starting to reek pretty seriously and they're just dying to load up with flowers.. not a good time for me to be goofing around with experiments. But it seems there's no single simple answer, so there we are.

[Weedhound]

Well I hope latewood or somebody hops in with an answer cause now it's bugging me too!

[MisterE]

Well the baking soda SEEMS to have done the trick! I took about half a teaspoon and mixed it with a few tablespoons of water and stirred it a bit and dribbled in a SMALL amount. My ph went up, but it's STAYing up is the important thing.

I believe the article I read on icmag was correct, about it acting as a PH buffer.
It went up quickly, and in fact I'm about to go Down it, lmao.

Res change tomorrow with any ph up adjustments using baking soda and a prayer ;)

[Weedhound]

Good luck.....update!

[MisterE]

PH was exactly the same this morning as it was last night, so it looks like the buffering was what I needed.

Ok, today I did a nearly full res change. I left about 2 gallons in there. I used a slightly weak lucas bloom formula with about 8 gallons of RO water. (I used a formula for 7 gallons when I have a 10 gallon system). Poor plants have been through alot, so I'll see how they behave.

After it had circulated awhile and I adjusted the water level, I ph up'd using a few ml's of the baking soda and water. It took very little, and I'm currently sitting at 5.7PH, 650PPM.

[Weedhound]

I had trouble with ppms at that number when my plants got to be about 7 weeks old and that's what caused the deficency in my last grow....keep a careful eye....

[MisterE]

5.7 and 640ppm now. Looks like so far anyway the ph is nice and stable.

I watch them all day long pretty much, so no trouble there. I had trouble a couple of weeks ago when I had stronger nutes, so I'd rather go light than too strong.

[MisterE]

5.8 and 620ppm. Looks like everything is working, my plants are taking up nutes and hopefully well on their way to a healthy flower cycle.
Now we know what to suggest if others ever run into the same problem and have beat their head against the wall trying to figure it out.

[Weedhound]

Thank god....never knew the baking soda I was using did that....

[MisterE]

5.7 and 660 today. I topped up with nuted solution. They're drinking it up really well now :)

Weedhound, it's possible that your water is buffering PH already too. Here is a great article on water, and where I finally got the idea to try baking soda (never would have occured to me, as the common good advice is always stick with the professional ph adjusters): http://www.icmag.com/ic/showthread.php?t=23357

My plants are bursting with fresh growth now.

[Weedhound]

Well I read the water article Mr E but there are still some things I don't get....all those ferts etc are supposed to already have ph buffers in them. Why aren't they working for you??!! I did notice however that when I mix a new batch of ferts the ph is usually low and I bring it up with baking soda before I do a res change so perhaps I've just plain been way ahead of you the whole time.....the last few times I have done res changes I have not had to raise my ph first and now thinking about it I realize that the ph is not staying as stable at first as it was but settles down pretty well after I adjust it with ph down for the first time. (Always goes up.... never down so ha)

[MisterE]

You may have been ahead of the game (only way to know I suppose is try store bought PH Up if you dare and try, lol), or your basic water chemistry may include sufficient buffers already. You'd need much more than a basic PH probe to test such actual numbers I think.

But also, my WORST case of ph dropping like crazy was when I was using plain RO water, no nutes at all. And it was dropping full points in a day (6 to 5 etc).

I'm glad to say though that now my PH is absolutely rock steady! Seriously like a miracle.

I think the bottom line really is that if you see CRAZY swings where you have to adjust the heck out of it one way or the other constantly, you very well may simply lack enough PH buffering in your *water* (regardless of nute brands), so a small bit of sodium bicorbonate could very well help stabalize it.

I've flipped over to 12/12 starting today, and replaced my MH with my HPS. These plants are going to be twice as big as I'd wanted them to be, but I can hope for a quick flower cycle I guess.

[Weedhound]

Yeah more buds, more trichomes what a shame :D The fun part is unprying all the branches and leaves that grew up into the light and ceiling beams.
Sure glad your grow is back on track!

[MisterE]

lol true. I'll have more harvest, but boy is it ever gonna stink in there.. Plus the light wont penetrate as much, but I'm supplementing it with side lights. I had to drag the tub 6 more inches from the wall because some leaves were touching this morning.

Since 2 plants are in only a 10 gallon tub, they're shoving away from/against each other, with leaves and branches all mashing together. The top looks almost like a scrog with no screen, lol. Not really, but bushy bushy. This strain would definitely be excellent for outdoor. It'd be round.

PH is still rock solid wherever I set it. The issue I'm working to keep up with now is topping up the res, because they're drinking/eating like pigs! LOL

[MisterE]

Oh, I'd forgot that you asked for pics.

Dec 2nd on left, Jan 2nd on right (best I could do with main light on and POS camera). No training or topping at all.

[Weedhound]

Ph problems or not--good job! Is the second pic one plant or two? It looks just fine for two plants but quite the beast if it's only one.

[MisterE]

It's both plants in the same little container still. Camera sucks, but there's branch tops everywhere and they're just as full on the opposite side, but I can't get back there, lol.

I rigged up a little shelf for my fan so I can remove a little cabinet that you can almost see in there, to give them the full 5 foot width to grow into.

I think this strain (alien's NLX) would scrog really well. I'm anxious to see how they fill out. Hope they can handle the weight they're going to be carrying.

[MisterE]

PH still completely fine. All I've needed to do still is up it slightly with baking soda dissolved in water when I add nutes, or top up the res. making it drop slightly.

Plants are really exploding. At least 2 to 3 inches growth overnight. One branch from the third node is now taller than the plant tops lol. It's opposite branch is quite a bit shorter due to being on the outside edge of the lights "sweet spot" with only supplemental side lighting (and a thick canopy).

Harvest will be quite affected by using only 400 watts (and it's only 2 plants). Next time, short clones thrown into flower quickly, and/or only 1 large plant.

[Weedhound]

Sounds like it may be time for bigger "light guns"