low ph the problem?

[greengiant1980]

i have 6 seedling (arjans strawberry haze) that are 2 weeks old. over the last couple of days i have noticed a slight yellowing in patches on the leaves of 2 of the babies. i tested the soil ph which came out at exactly 6 which i think is the problem. it is a pre fertilized soil im using so i've ruled out deficiencies. if ph is the problem is there a short term solution to this problem as i cant get to a grow-shop for a week or so?

grow room temp: 82f
400w hps 18/6

greengiant1980 Reviewed by greengiant1980 on 09-22-2009. low ph the problem? i have 6 seedling (arjans strawberry haze) that are 2 weeks old. over the last couple of days i have noticed a slight yellowing in patches on the leaves of 2 of the babies. i tested the soil ph which came out at exactly 6 which i think is the problem. it is a pre fertilized soil im using so i've ruled out deficiencies. if ph is the problem is there a short term solution to this problem as i cant get to a grow-shop for a week or so? grow room temp: 82f 400w hps 18/6 Rating: 5

[greengiant1980]

heres a pic, i finally got my cam sorted.

[Italiano715]

i have 6 seedling (arjans strawberry haze) that are 2 weeks old. over the last couple of days i have noticed a slight yellowing in patches on the leaves of 2 of the babies. i tested the soil ph which came out at exactly 6 which i think is the problem. it is a pre fertilized soil im using so i've ruled out deficiencies. if ph is the problem is there a short term solution to this problem as i cant get to a grow-shop for a week or so?

grow room temp: 82f
400w hps 18/6

CanCom 'Copy-n-Paste' Troubleshooting Forms


You'll definitely want to bring your pH to at least 6.3 at minimum IMO and at 6.8 MAX...I shoot for 6.5 as that's in b/w :jointsmile:

Also, the soil could be a possibility but doubtful, being that your just now seeing these symptoms. Usually if the soil is too harsh you would have seen those problems in the seedling stage.

Either way, fill out the form for a definitive answer!

[Italiano715]

Adjusting pH Of Marijuana Grown In Soil

A good way to stabilize soil is to use dolomite lime (calcium-magnesium carbonate). Dolomitic lime acts slowly and continuously, so soil will remain pH stable for a few months.
Using fine size dolomite lime is important, coarser grades can take a year or longer to work. You can find fine size dolomite lime at any well stocked garden supply center.


Dolomite lime has been used by gardeners as a pH stabilizer for many years. It has a pH that is neutral (7.0). When added to soil in the correct proportions, it will stabilize soil at a pH near 7.0.

When growing in containers, add one cup of fine dolomite lime to each cubic foot of soil. Mix the dry soil thoroughly with the dolomite lime, then lightly water it. After watering, re-mix it and wait for a day or two before checking the pH. When growing in an outdoor garden, follow the dolomite lime manufacturers instructions.

Lowering soil pH: small amounts of composted leaves, cottonseed meal, or peat moss will lower the pH of soil.

Raising soil pH: small amounts of hardwood ashes or crushed oyster/egg shells will help to raise the soil pH. Hydrated lime can also be used to raise the pH of soil. In containers, use no more than 1/8 cup of hydrated lime per cubic foot of soil (per application). Mix it into warm water, then apply the water to the soil. When growing in an outdoor garden, follow the manufacturers instructions.


Wait at least a day or two before checking the pH level of soil after attempting to raise, lower or stabilize it. If adjustments still have to be made, use small amounts of whatever material you are using. Don't try to adjust the pH more than 0.1 every two days.

[eastbaygordo]

The poster who said garden lime is good is correct. I think 6.0 is close enough but if you want perfection test your run off to see how the nutes and soil are reacting together to change your PH.


Also, test your incoming water before and after nutes and adjust accordingly.

[greengiant1980]

thanks for the replies, fingers crossed they wont get any worse