Water

Types of Water

• Tap Water: This is the water that comes out of your faucet. Most tap water has calcium, magnesium, fluoride, and other “stuff” in it. This water is usually at 30 - 300PPM depending on where you live.

• 0PPM Water: Filtered, RO, Distilled, all starting at 0PPM.

  • Filtered Water: There are many types of water purifiers on the market, I used to use a “Zero Water Filter”. Put tap water in, filtered water comes out. This water is at 0PPM. Depending where you are in the world your water may be better or worse in quality. This option may not be economically viable over time, if you have very hard water, you will go through these filters super fast.

  • Reverse Osmosis Water: There are many types of affordable reverse osmosis systems on the market as well. You plug these systems into your hose or your sink, and clean water comes out. This water is at 0PPM. Usually, this is a lot faster than having to filter your water pitcher by pitcher. I’ve installed an RO system now and it’s AMAZING. I use the pure blue H20 system because it was on sale at Costco. If you can’t install one, I’ve seen people rave about these countertop ones, it just takes a bit longer. I’ve used one for 1.5 years now, using likely 5-10 gallons per week, and I’ve not had to change the filters yet. These are so worth the money.

  • Distilled Water: This is the water you get in the gallon jugs at the grocery store. This water is at 0PPM.

Tap water has a lot of added “stuff” like fluoride, chlorine, calcium, and magnesium. If you've ever watered your plants and see a white buildup at the top, and that is the excess salts and minerals that the plant can’t absorb. The reason I like to use filtered water is because some plants are very sensitive to excess minerals in tap water. I've measured my water and it's around 160PPM.

I would recommend using any type of 0PPM water when you are mixing your nutrient solution. If you want to use rainwater instead that’s great as well, but do know that sometimes rainwater has a lot of “stuff” like pollution if you live in a big city.

Protip: Save some gallon jugs and fill them with filtered water from your pitcher to save time. I also make a few gallons of nutrient solution at a time and save it in gallon jugs, it should keep for a few weeks.

Calcium and Magnesium

This is extremely important if you use filtered water for your plants instead of tap water. Remember that filtered water is at 0PPM, which means it has no calcium or magnesium left. You must add that back into your nutrient solution.

• Calcium - Responsible for holding the cell walls together in plants. If your plant is calcium deficient, it may have deformed leaves.

• Magnesium - Very important in photosynthesis. If your plant is magnesium deficient, it will show signs of browning leaves.

Some fertilizers have added calcium/magnesium so you need to read the label and figure out if you need to supplement or not. For example, K-Lite is formulated to include additional calcium so you will not need to supplement. I followed the direction on General Hydroponics CalMagic and found that their dosing instructions resulted in 200PPM. I scale that back a bit for my orchids but use the recommended amount for everything else.

Calcium and Magnesium supplement has to be mixed into the water first to prevent nutrient locking. This is when in chemistry, one element bonds to another element to make a new element so the order of what you mix matters.

Fertilizers and Other Additives

Primary Fertilizer (Macronutrients)

The General Hydroponics line of fertilizers (FloraMicro, FloraGrow, FloraBloom) is very popular with the houseplant community. Another favorite of mine is the MSU orchid fertilizer (13-2-15). It’s formulated for houseplants as well as orchids, with pretty high levels of calcium - but I still supplement. One of my new favorites is K-lite. I mentioned this above - I’ll dedicate a section to K-lite down below. It saves time by combining fertilizer and CalMag, the breakdown is 12-1-1-10Ca-3Mg. Others have found a lot of success with Foliage Pro, another hydroponics fertilizer by DynaGrow. These are what we call NPK fertilizers that give macronutrients to the plant. These macronutrients are:

• Nitrogen (N) - promotes foliage and leaf growth.

• Phosphorus (P) - promotes a strong root system.

• Potassium (K) - promotes overall hardy growth.

Additives

The following additives I’ve found to be useful when growing in Semi-Hydroponics.

• Rooting Stimulants - Reduces plant transplant shock and promotes strong root growth. Both RapidStart and Kelpmax are my favorites. RapidStart is formulated for root growth, and Kelpmax works similarly and it’s very smooth and doesn’t have chunks like some other seaweed products on the market. I don’t use Superthrive like others. This is why.

• Fulmic Acid / Fulvic Acid - Increases the plant's ability to take in nutrients and is very effective when used together with seaweed extract. My favorite is Mr. Fulvic. (Mr. Humic is the same product, I asked, it’s a branding / state regulation thing.)

• Potassium Silicate - promotes stronger cell walls and increases resistance to pests. If you are using this, make sure to add it before Calmag. I used to use sturdy stalk quite a bit, but with the way I mix now, it’s harder to use this product so I’ve skipped it for the past year.

• Probiotics - increases better root zone environment with beneficial bacteria. I use Quantum Orchid and recently I’ve started using Orca. Orca is unique in that it blends together 4 highly effective endo mycorrhiza species with 11 super aggressive bacteria strains. (Don’t try to mix mycorrhiza and beneficial bacteria yourself, leave this one to the experts.) This is a highly rated hydroponics product to keep bad bacteria that causes root rot out of your pots.

Scroll down to see the plant juice formula and how much to add to a gallon of water.

Adjusting the pH

After your mixture is at the right PPM and mixed, it’s time to finally adjust the pH of the mix. The reason we need to adjust the pH is because nutrients are absorbed by the plant at specific pH ranges. For example, if you’re growing potatoes, your soil should be at pH 4.0 - 6.0, and if you’re growing mint, it should be at pH 6.0-8.0. Also different elements are absorbed at different pH levels. For example, calcium and magnesium is ideally absorbed better in neutral to alkaline conditions while iron and copper and zinc are better absorbed in acidic to neutral conditions. To cover a broad spectrum of plants and nutrient needs, most hydroponic growers will target a range of pH 5.5 - 6.5.

The products that are used most often by hydroponic growers are General Hydroponics line of pH up and pH down. You will also need a pH meter, or use pH strips to measure the pH level of your solution. It’s fairly easy once you do it a few times. Put the pH meter in the solution, add pH up or down as needed to reach your desired pH level. I try to hit about 5.7 or 5.8, my observation is that the pH of the nutrient solution will increase with time.

Once pH adjusted, add the nutrient water to the water reservoir of your plant and that is it!

HOWEVER… there is a lot of information recently about the pH of the root zone versus the pH of the reservoir water, and the finding is that pHing your reservoir water in semi-hydroponics is unnecessary. I would encourage you to do your own research here and experiment with pHing and not pHing. I find that with my normal nutrient mix, I end up in the 5.0-6.0pH zone most of the time so I skip pHing now. Remember tho, it may take up to 6 months - 1 year to see the results / side effects of this.

Source: First Rays - Ray has been growing in semi-hydroponics for decades (I believe he actually coined the phrase semi-hydroponics.) He has an experiment with pH measurement that I encourage you to do yourself. His finding is that the pH of the pot fluctuates depending on the time of the day, so all of the work you put into pHing your nutrient solution may not be helpful and might be a waste of time.