About pH Up and pH Down
pH Up and pH Down let you bring your nutrient solution into the right range before you feed. Plants can only take up all the nutrients you give them when the pH is right, so a quick check and a small adjustment every time you mix a feed is one of the easiest wins in the grow room.
We stock pH Down and pH Up from Growth Technology, Mills and Essentials LAB, an organic citric acid pH Down from Plagron, and Athena Balance, a pH regulator that buffers your water before nutrients go in. All work in hydro, coco and soil feeds.
Whichever you choose, add a little at a time, stir and test again with a calibrated pH meter.
How to choose pH Up or pH Down
Test your mixed feed first. If the reading is too high, you need pH Down. If it is too low, you need pH Up. Most growers keep a bottle of each on the shelf.
| Product | What it does | Key fact from the maker | Sizes |
|---|---|---|---|
| Growth Technology pH Down | Lowers pH | Concentrated, so a small bottle goes a long way | 250ml, 1L or 5L |
| Growth Technology pH Up | Raises pH | Easy to dose a little at a time | 250ml or 1L |
| Mills pH Down | Lowers pH | Concentrated liquid for hydro, coco and soil feeds | 1L |
| Mills pH Up | Raises pH | Concentrated liquid for hydro, coco and soil feeds | 1L |
| Essentials LAB pH Down 30% | Lowers pH | 30% phosphoric acid: small doses adjust large volumes | 250ml or 1L |
| Essentials LAB pH Up | Raises pH | 50% potassium hydroxide: small doses adjust large volumes | 250ml or 1L |
| Plagron Lemon Kick | Lowers pH | Organic pH Down made with citric acid, kind to beneficial soil life | 1L |
| Athena Balance | Regulates and buffers pH | Potassium silicate based, added to plain water before nutrients | See product page |
Bigger reservoirs: the Essentials LAB pair are highly concentrated, so small doses adjust large volumes. Organic soil growers: Plagron Lemon Kick uses citric acid. RO or very soft water: Athena says Balance is especially useful with RO water, stabilising your water before you add feed.
pH Up and pH Down FAQs
What pH should my nutrient solution be?
Mills recommends 5.5 to 6.5 for most plants, and Plagron says Lemon Kick brings pH down to the ideal 5.5 to 6.5 range. Always follow the guidance from your nutrient maker.
Do I add pH Up or pH Down before or after nutrients?
After. Growth Technology advises mixing your nutrients first, then adding pH Up or pH Down a few drops at a time. Athena Balance is the exception: Athena says to add it to plain water before any nutrients or additives.
How much pH Down or pH Up should I add?
It depends on your water and your feed, so there is no fixed amount. The makers advise starting with small doses, mixing thoroughly and testing again to avoid over correction.
Do I need a pH meter?
Yes. Check every feed with a calibrated pH meter such as the Bluelab pH Pen, and calibrate it regularly with pH buffer solution. See all our pH meters and testers.
Are pH adjusters safe to handle?
They are concentrated, so handle them with care. Growth Technology advises wearing gloves and eye protection when handling. Always read the label before use.
New to feeding? Our guide on how to read a nutrient feed chart explains EC and pH targets, and you can browse our base nutrients to go with your pH kit. Free UK delivery on orders of £94.99 or more (large 19L to 25L containers have a delivery charge shown at checkout), we price match, and Click & Collect is available from our West Bromwich store.
Need advice? Visit our West Bromwich store, call 0121 553 7872 or WhatsApp our experts.