PH Testing and Adjustment

PH is something most people don’t consider but if you are going to grow marijuana inside then you must learn about PH. Having a extreme PH level in any direction will be fatal to your plants! Marijuana likes a PH in the alkaloid direction or a little more alkaloid than acidic. Neutral is about 6 on the PH scale so you would be looking at a PH of 7 for marijuana. As long as you are between 5 and 7 on the scale you should be OK.

In chemistry, pH is a measure of the acidity or basicity of a solution. Pure water is said to be neutral, with a pH close to 7.0 at 25°C (77°F). Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline. pH measurements are important in medicine, biology, chemistry, food science, environmental science, oceanography, civil engineering and many other applications.

PH of water tends to stay the same unless you say ad chemicals to it like fertilizer. Generally I have found that the PH of my nutrient solution stays relatively the same but dealing with evaporation you are going to have to ad water and nutrients every so often and that depends on your system. Make sure you know how much nutrients you are adding per gallon so when you ad a gallon of water to your system you can premix it and dump it in. This in itself should not change the PH of your nutrient solution too much but it’s a good idea to check your pH anytime you make any changes to your nutrients. You should also check your PH every week just to be sure something has not caused a change.

There are a lot of products offered on the market to increase or decrease PH but a simple and cost effective way is Vinegar and Baking Soda. Vinegar is an acid base substance and Baking Soda is more the opposite with a natural PH of I believe 8.2 on a PH scale. When choosing a vinegar use distilled vinegar. When you check your PH with either test strips of a PH meter and you determine that your PH is to acidic, (below 6) then ad some baking soda to bring your PH to the alkaline direction. (above 7) If you are testing the other way and you want to bring your mixture down ad a little vinegar. You don’t need much either. Test your PH after mixing and before you turn your system back on or starts it’s cycle again.

If you do want to make your own PH adjustment mix here are some recipes and some warnings. Not only is it time consuming, it’s dangerous! Buy some PH up or PH down before attempting this!

PH Down

Supplies:

(1) 2 L Bottle – Labeled as ACID – $1
(1) Funnel – $1
(1) Box of battery acid – Auto Part Store – $7
(1) Set of measuring spoons – $1
(1) 1 gal of distilled water – $1

Grand Total: $11

Precautions:

Use safety glasses, rubber gloves, and well ventilated areas.

NEVER POUR WATER INTO ACID!!!

Always pour SMALL amounts of acid in LARGE amounts of water, SLOWLY!!!

Procedure:

Fill the 2 L bottle with about 3/4 full with distilled water. This bottle should already be labeled for its intents and purposes.

Prepare your battery acid and measuring spoons.

With your measuring spoons mix the acid from the store with water in a 1:10 ratio. That is ONE part ACID, TEN parts WATER.

For those lacking mathematical skill: ~180 mL of sulfuric acid in the 2 L bottle.

This should bring the solution from 33% acid to 3.3% acid. Still, VERY DANGEROUS TO STORE AND HANDLE.

Slowly pour the acid into the funnel, into the 2 L bottle making sure that the bottle doesn’t over-heat. If it does, you are going to the hospital and forget any holiday pictures from now on.

Once you have enough acid in the container to have the 10:1 ratio, fill the remaining volume with distilled water. Seal the lid and gently turn the bottle up-side down and back until fully mixed. Do this slowly.

PH Up

Supplies:

(1) 2 L bottle – Labeled as BASE – $1
(1) Funnel – $1
(1) 2 lb dry sodium hydroxide by Roebic – Lowe’s – $12.98+ tax
(1) Set of measuring spoons – $1
(1) 1 gal of distilled water – $1 (FREE! with a clean dehumidifier or reverse osmosis filter on a water outlet.)

Grand Total: ~$18.00

Precautions:

Use safety glasses, rubber gloves, and well ventilated areas.

NEVER POUR WATER INTO A BASE!!!

Always pour SMALL amounts of base in LARGE amounts of water, SLOWLY!!!

Procedure:

Fill the 2 L bottle with about 3/4 full with distilled water. This bottle should already be labeled for its intents and purposes.

Prepare your caustic base (sodium hydroxide, or lye) and measuring spoons.

SLOWLY pour (1) 1 tbsp of your base into the 2 L bottle. Slowly swish the solution to ensure a good mix of the dry granules. After all of the base has been mixed in slowly add more distilled water until nearly full.

Remember, if you mix this stuff too fast it will explode.. and possibly kill you.

Now, get an eye dropper and use three drops at a time on a test gallon to figure out the concentration. Unless you have the equipment to measure the granules by mass and calculate molarity of the aqueous solution you will have to test the strength of every batch. The good thing is, this is so cheap and effective it will be worth it.

Now you have enough pH Up for 2 years of constant use. This means 2 years for heavy hydroponics, a decade for soil if you ever need it.

Now, there is a better option than the sodium hydroxide. There are plenty of aquatic shoppes that stock calcium hydroxide, which would be a better choice since plants need the calcium anyways. You can also use potassium hydroxide.