How much to fix my pH?

[Natural]

Ok, I'm using light warrior fox farm soil and all fox farm nutes with RO water.
I noticed some pH problems from the looks of my leaves and tested the run off.

I'm below 6.2 (as low as the testing strip box lists...) Probably way below it, because mytest strip is yellow and the 6.2 color on the chart is about light orange...

Dolomite lime or what?

My plants are in 1 gal grow bags...

 

[10k]

Dolomite lime or what?

yes, water about a teaspoon into the growbags and recheck your runoff.
repeat if needed.

 

[Verite]

I always found those strips and the bi-metal probe meters to be inaccurate enough to produce unfriendly results. For what it would cost you to use the strips 6-12 months you could have bought a Hanna Checker1 ph meter for as little as $23 bucks and shipping. The Checker1 reads to hundredths in ph.
http://search.yahoo.com/search?p=hanna+checker1+prices&fr=yfp-t-501&toggle=1&cop=mss&ei=UTF-8

 

[Natural]

Ok, after adding 1 tbs of dolomite lime to my top soil and watering... the pH problem is still there. After running water through, I was still a little below 6.2 on my testing strips. It was pretty close to the color of 6.2 though...

Also, after I added the dolomite lime and watered, I noticed that within 24 hours some of my lower fan leaves had turned completely yellow. (I'm in day 35-40 flowering, but none of them were yellow before I added this)

-Should I add more dolomite lime?
-Is it safe to water again? I watered about 2 days ago and I usually water once every 5-6 days... I don't want to over water them too! The top soil is dry, but half inch below the top of the soil is still damp.

I can shoot a pic in about an hour when everyone is in bed...

 

[Natural]

Pics

 

[sproutco]

2 birds with 1 stone...

2 birds with 1 stone...

Don't apply anymore lime. It is slow to react so you have to give it weeks. You did add a large dose of both calcium and magnesium to the soil. Remember, potassium, calcium, and magnesium all compete with each other to get in the plant. You want a ratio of maybe 4:2:1 potassium to calcium to magnesium in the soil mix. You can see you want twice as much potassium as calcium and twice as much calcium than magnesium. You need to increase potassium in your soil to boost levels because of the lime. Best thing may be potassium nitrate 13-0-44. It is a highly soluble form of potassium. This is probably the most used ingredient in normal store bought ferts. Peters, for example, uses this. This is the ingredient in some stump removers at hardware stores like lowes and homedepot. Grant's dexol and spectricide are some brands but there could be others. Check the label to see if it says potassium nitrate. Apply 3/4 teaspoon per gallon of water instead of the regular ferts. (only use 1/2 teaspoon gal on tender seedlings) This provides 143 ppm nitrogen and 400 ppm potassium. You can do this several times as needed. As a added bonus to your situation with ph, potassium nitrate contains nitrate nitrogen. When plants take this up, the ph of the soil mix will go up.

 

[Natural]

Thanks man!
Do you think "Beastie Bloomz" would suffice? It's 0-50-30 and it says to use half way into the flowering stage (I'm at halfway).

My car is in the shop probably for today and tommorow so I'd really like to fix this problem but have no way of getting to any stores!




Also, I'm planning on transplanting a 3 week old plant in about 1-2 weeks depending on when I can finish up my veg cab. Should I add dolomite lime to my new soil (Foxfarm Light warrior) to take care of the pH problem I've been having with it on my flowering plants?

 

[sproutco]

The 13-0-44 is nitrate nitrogen. This will raise your media ph slightly like your trying to achieve. This fert is called a "toner" because it doesn't encourage lush growth. You probably don't need a blast of phosphorus with 0-50-30. I guess your already applying high phosphorus bloom ferts. This builds up in the soil mix. Its actually good to every fourth fert or fifth fert or so apply something without p. Too much p results in micronutrient disorders starting with zinc deficiency. I went over to the Lowes and they had spectricide stump remover. When I peeled the label open it stated potassium nitrate. That is what you look for.

You can add lime at planting time to your mix if needed. Don't use more than 1 1/3 tablespoon per gallon of soil mix. (10# per yard) Be sure to mix really well so its uniform in the way its mixed.

 

[PersonalSmoke]

I'm not claiming to be an expert or anything (I'm not, by a longshot), but take sproutco's advise with caution. He knows a lot about botany but like others have pointed out he doesn't even grow weed. I took his advice and my plants got burned up so just be careful. If i were you I'd hit up the old farts thread.

By the way, I bought the Hanna Checker1 Ph tester and can't reccomend it enough. Very much worth the money.

 

[sproutco]

You can buy potassium nitrate with micronutrients too if you want to get fancy. http://www.plantmarvel.com/130044_hi_k_spec_tech_sht.pdf

Click on it to enlarge


Notice it says potential bascidity 450# on there. This is alkaline and raises ph. (it would say potential acidity if it were an acid fert)

 

[Guest]

For anyone in the future who reads this thread. Medium pH is absolutely essential to growing healthy, vigourous plants with optimal bud weight. Happy roots are required before getting loads of top quality marijuana.

Don't hesitate to buy quality pH meters....they're worth their weight in bubble hash.

And never assume that soils come with enough dolomite lime added already. Get that Dolomite lime ready and check it with the pH meter.

1-2tbspn per cubic foot of soil mix should generally do the trick.

 

[sproutco]

I'm not claiming to be an expert or anything (I'm not, by a longshot), but take sproutco's advise with caution. He knows a lot about botany but like others have pointed out he doesn't even grow weed. I took his advice and my plants got burned up so just be careful. If i were you I'd hit up the old farts thread.

Here is what I told you...

Your going to be left guessing with preenriched soil like ffof. You should put them in a neutral soil with nothing but dolomite lime or gypsum. Then add your ferts in the water.

If you followed my advice, there would be no way your plants could "burn up". I advised you not to add ferts at planting to the soil mix. If you put the ferts in the water you could easily leach the soil if they began to burn and you used to much.

 

[PersonalSmoke]

Well ok if you want to call me out on it:

With seedlings this size and your sure that's your fert numbers, feed 12 ml per gallon of water. (100 ppm nitrogen) Adjust ph after adding the ferts to about 6 using an acid or base. Things to use are in my signature below.

I replied:

Also, I trust your knowledge and gotta say thanks for this help, but should i really still fert them? Some of the smalled plants did get burned from just that small dosage, wouldn't 12ml be pushing it?

You replied:

You should check the numbers on the bottle and see if it is the same numbers as this:

Pure Blend Pro Grow
3-1.5-4
1.0625 grams/ml
@10ml/Gal
N 84
P 18
K 93
Mg 14
Ca 28
Fe 0

10 ml per gallon gives you 84 nitrogen. You want about 100 ppm nitrogen for seedlings. 100/84 x 10ml = 12 ml per gallon you would use. If you got burn from just a little ferts, the soil may still have some nutrients so try 50 ppm nitrogen or 6ml per gallon. Surely after a month, you will need to be adding the 100 ppm nitrogen at least. Once they get larger, go to 150 ppm nitrogen. This will be plenty for growth.

This is one reason I don't like soils with ferts at planting. It leaves you guessing what and when to add ferts in your water.

So try 6ml a gallon on the small seedlings and 12 ml a gallon on the larger seedlings. Boost the small seedling rate once they start getting a little older/larger.

The entire time they had ph problems. Some others advised me to get a better ph meter, I did, and now they are getting better. Like I said I'm no expert, but I'm just warning this guy to wait until someone who knows a fair amount about growing marijuana has a chance to take a look.

edit: Sorry if I hijacked your thread, I didn't mean to.

 

[sproutco]

Pre enriched soil is what got you. See how to make a soilless mix in my signature below...

It is probably best you do not add blood meal or bonemeal or anything else other than the lime and gypsum into the soil before you plant. You do not know how much nutrients are present and being released. You end up having to guess at what to add in your nutrient solution. By leaving out added nutrients mixed into the soil, you control what the plants get through your nutrient solution exactly.

 

[Jesusbuiltmygro]

Why use RO

Why use RO

Unless you original water source is very bad you probably wouldn't have problems if you just used the standard hard water that comes out of most taps.

If your run off low is because of two things. One the mediums PH, but lets not forget about the source water PH.

In most cases RO brings down your PH, so this is likely pushing you over the edge. Whats the PH of the water before you water your plants ?

Also what about the possibility of being root bound. Root bound plants exhibit simlar symptoms of plants with the wrong PH. This is because in both cases nutrients are being locked out.

Having a PH meter is worthy investment over PH strips, but that's not to say you need one to grow good weed, just that your learning curve is reduced and your ability to adjust to new grow conditions is heightened because you can take accurate measurements. Those 50-60 dollar Hanna water proof models are good buys. Don't get the real cheap Hanna though with the long slender probe, they break a lot and need calibration more often. Def. try to get a meter with temperature compensation.

The low PH is a result of your source water being run through RO and the addition of your nutes. Your nutes are probably meant to be added to standard hard water which has a higher PH of 8+. You add the nutes and it drops your PH to 6.5 ish, however with RO water your PH is closer to 7 and could be dragging you below the PH level.

However, I'd still wonder if PH is really even your problem. While I'd say 6.5 i ideal. PH of 6 shouldn't be all that much of a problem. Unless your PH is starting at 6 and going down over time. The range for PH is 5.5-7.5 and while I grow around 6.5 I've heard of people using the lower end of that range with success. So....

Back to root bound. Look at the top of the soil. When plants get so root bound that they show symptoms of nutrient deficiency sometimes it's possible to see tiny root tips which have actually grown up through the surface of the soil and died. At first you might mistake them for the early signs of mildew on your soil, but a closer looks shows they are in fact dead root tips. If you see these you are almost certainly root bound. However this is not a reliable way to tell.

To be sure you should take one of your plants out of it's container and observ the roots. With some study you can actually tell which direction they;ve been growing. If they look like mess of spiderwebs on the outside of the root ball they are probably root bound.

If your in bloom this is a problem. Not using RO water will also add more magnesium and calcium to your plants. Overall your plants don't look too bad really.

If you find other things don't help you should look closely into the chance they are root bound. With your small container size it is a possibility. To grow in one gallon containers you must keep your plants small.

The normal procedure for root bound plants is to replant them and in the process prune their roots. What happens in the roots grow out to the edge of the container and then curl back inward once they grow all around the edges of the container. They grow back toward the root ball and interfere with growth and nutrient uptake.

If your runoff is low it seems to more it's more likely because of your water source than your medium. Especially after adding lime the PH is still acidic and you using such small containers. I think it's the water and/or being root bound. Avoid using RO water if you can. You want you water to have minerals in it. What sense does it make to purify the water and then add back most of the minerals you just filtered out.

Most growers are using RO as a means of PH control and this is bad form really since RO removes PH buffering. Probably more of a consideration in hydro, but none the less too many growers use RO when they don't have to.
If you need chlorine filtering simply let your water sit out for 24-48 hours.

You should find that since most nutrients are designed for hard/tap water that RO water just causes problems. PH swing and stressing your plants is part of a set of problems that is RO water.

I would only suggest using RO water if your source water is over 400-600 ppm or has a ph of 9+.

I'd recommend newbies stick with organic soil mixes and not try to make their own until they've mastered the other element of organic growing. Making your own mix is really the pinnacle of organic mastery and while it's not hard to pull off it's easy to screw up and correcting soil conditions after the fact is A LOT harder.

The trick is really timing. If you had flowered sooner and used larger containers you'd probably have no problem.

I recommend nurients such as earth worm castings, kelp meal, phosphate and nitrogen bat guano, greensand, and fiush emalsion

 

[Natural]

Ok, ran into some problems...
Went to home depot. The only stump remover they had was "Grant's stump removal", which listed no ingredients... I even peeled the label off to see if they were behind the label, no ingredients...

I just tested the pH of my tapwater after my buddy stopped by on his way home from work (pool guy) and we tested it. It came out to be 8.2 should I be using this tap water or stick to the RO water?

Also, it is very possible the plants may be rootbound... I can't transplant into bigger pots as of now though, no more room in my cab. I could however cut some rootmass off, put new soil in and replant if you think it would be beneficial during flowering...

 

[Chronic Newfie]

I could however cut some rootmass off, put new soil in and replant if you think it would be beneficial during flowering...

Thats what I was thinking. I read about something like that in another tread. I'll try to find it. Would this cause stress? I've never done it so I'm only speculating.

Good Luck.

 

[sproutco]

Grants stump remover = potassium nitrate

Here is what Dang911 at another forum said...

Its pure KNO3, I work at Home Depot and have the all the MSDS's. The first thing I did when I started working there was to look up all the unknown chemicals they sell under different names or products. HEHE

Don't cut the rootball.

I am really stoned.

 

[sproutco]

Pic sucks. Grants stump remover...

 

[kokua]

Jesusbuiltmygro is right on

Still pimping the stump remover ey sproutco? Natural...I would be hesitant to dose my plants with something that is formulated to break down the wood in old tree stumps. I will go out on a limb here and say that I am not the only one...

sproutco.....While your intentions may be good in trying to help other growers, without the proof to back up a method, whether it be a new or old method, leaves the proposed/suggested method in question. As a grower who most likely has alot more grows under their belt, along with univeristy studies regarding horticulture, I must....with all fairness in mind....say to 'all growers seeking grow information' on icmag that unless the person proposing such can back it up with credible info and pics, please do not take any such advice to heart, whether it be this thread or another. If someone can't back up their theory/method...then that should tell you something about the proposal.