Do pH Dynamics And Adjustment

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1- What is pH?
Answer: pH is the measure of acidity/alkalinity of a solution.

Can you explain this in a little more detail?
Answer: Specifically, pH is a measure of the hydronium ion H3O+. It is based on a logarithmic scale from 0 to 14. "Pure" water has a pH of 7.0. If the pH is less than 7, the solution is acid. If the pH is greater than 7 it is alkaline. Because the scale is logarithmic and not linear, a pH of 6 indicates ten times more H protons than a pH of 7, and a pH of 5 indicates 10 times more protons than a pH of 6.

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2- What pH is best for growing plants hydroponically?

Answer: The ideal pH range for most hydroponic crops is between 5.5 and 6.5.

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3- How does pH level affect plant growth?

Answer: pH is important because it affects availability and absorption of several of the 16 atomic elements needed for plant growth. Maximum absorption of these elements is found at pH readings 5.5 to 6.5. When pH falls below this range many of the macro elements (N, P, K, etc) have less availability, and absorption of the micro nutrients can reach toxic levels.

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4- How do you change the pH?

Answer: pH is adjusted by using an acid to lower it or an alkali to raise it. General Hydroponics' pH Down and pH Up are designed for this purpose. Many acids and alkalis are extremely corrosive and dangerous, so care should be used if you are not using a product labeled for hydroponic use.

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5- What if I can not get any pH Down, and my system is running high?

Answer: Short-term solutions include citric acid (which degrades in solution) or sulfuric acid made for car batteries. Make sure this does not include any lead, and be very careful with this acid. Vinegar will also work, but generally, the effects are short term.

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6- How often should I check my pH level?

Answer: When first starting out it is a good idea to measure the pH of your water every day, until you get a feel for your system. Measure your water and then add your nutrients. Within an hour check the pH and adjust accordingly. Repeat this process until pH stabilizes. The liquid Flora Series has special pH buffers to help maintain a desirable pH. It is a good idea to note how much water, nutrients and pH modifiers are needed to obtain the desired values. After several "start- ups" you can generally get a feel for how much acid or base to use for your situation. Frequently pH stays within a desirable range for a considerable time, and then rapidly rises or falls to an extreme. This is usually an indication of the need to do a nutrient change. If you are using hard water, pH has the tendency to climb above 7.5. Sometimes this can be neutralized with acid, though one might consider adding a reverse osmosis unit in an extreme case.

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7- How much pH Up/Down is needed per gallon?

Answer: Start out with one milliliter per gallon. Wait 15 To 30 minutes, and test your water again. Frequently you will only need 1 to 2 ml of pH Up/Down per gallon of water. You may need additional pH Up/Down if you have hard water. The General Hydroponics Flora Series is pH buffered to facilitate keeping the pH in a favorable range.

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8- The pH in my system drops below 4 every few days after cleaning and refilling. How do I increase the pH and stabilize it?

Answer: The easiest way is to continue adding pH Up. This is generally fine because the additional elements that are added are potassium ions. Potassium is frequently the highest element in hydroponic nutrient solutions. Sometimes pH crashes because of the presence of a large amount of microbial activity in the nutrient solution. This is usually a result of poor maintenance of the system due to infrequent nutrient changes or other stresses. The best way to avoid this scenario is to keep a clean system with adequate nutrition.

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​Fight Pests with AzaMax

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With the indoor gardening boom, pests are taking over gardens more frequently. Pests seek out and find crops and will continue to do so unless they are stopped. In this industry, the most common pest is the spidermite; fungus gnats and thrips are gaining ground across the county as well. Using toxic pesticides that are harmful (and some that are even illegal) is not the answer.

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While every grower agrees that it is vital to control these bugs for the benefit of all, there are also beneficial insects and micro organisms that we must protect. AzaMax® is harmless to honeybees, earthworms, and soil microflora. It was in response to the concerns of pollution and toxicity that General Hydroponics added AzaMax to their product line.

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AzaMax is a highly effective pest control method designed to decimate pest populations. It is made from completely organic active ingredients, specifically one, potent, bio-compound found in Neem oil. AzaMax contains Azadirachtin A&B and more than 100 limonoids.

AzaMax targets spidermites, thrips, fungus gnats, aphids, whiteflies and many other airborne and soil borne pests. AzaMax is an antifeedant and insect growth regulator: it controls pests through starvation and growth disruption. It also acts as a good systemic product that plants can easily uptake through roots for efficient control of sucking, mining and leaf eating pests, a rare feature among biological or biochemical pesticides.

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AzaMax does not include hard chemical solvents, instead it uses food grade formulation ingredients.
AzaMax is the only smell-free product and does not freeze during cold weather.
AzaMax does not require any surfactants or sticking agents.
AzaMax is OMRI listed and licensed in all 50 states.
AzaMax is so safe and free of residue it can be applied on the day of harvest

Use AzaMax both as a preventative, and as a solution.

 

 

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Tips and Tricks - The Short List​

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Know what equipment you need and why
Know the nutritional requirements of your plants
Know the light/photoperiod requirements of your plants
Use a professional three part hydroponic nutrients product
Do not use additional nutrient additives your first time
Have a written plan/feeding schedule before you start
Have all necessary equipment and nutrients before you start
Garden indoors when it is 55*F or less outdoors (or use AC)
Keep the ballast for your lights in a different room
Check and adjust your nutrient reservoir solution every day
Minimize light exposure to your nutrient solution
Have an extra reservoir of plain water waiting for your next nutrient change
Change your water and nutrients completely every two weeks
Use a digital timer to control your dark period
Keep your dark period completely dark and uninterrupted
Clean and sterilize your system between crops
Quarantine new plants for two weeks before adding to your garden
Do not visit your garden after visiting another garden or being outdoors
Do not allow pets in your garden
Visit your garden after a shower and a fresh change of clothes
Make any visitors to your garden follow these same rules
Put a screen or filter over your air intake and exhaust (if outdoors)

Having a Plan

Hydroponic gardening success begins with having a solid plan. Having a plan means knowing your plants nutritional requirements and photoperiod requirements and having the supplies and equipment necessary to meet those needs. Actually having a written week by week feeding schedule, complete with nutrient strengths and nutrient changes, would also be very helpful.

Feeding/Nutrients

Know the nutritional requirements of your plants before you start. Know how strong the nutrients should be each week of your plant's life, and know what the nutrients should consist of each week. Many plants need more Nitrogen at first, than switch to needing more Phosphorus to produce fruit or flowers.

Do not try to mix up your own plant food. Instead, start with a professional hydroponic nutrients product. These are usually three part systems and are complete (and easy to use). My favorite is BC Nutrients. Once your hydroponic gardening system is up and running and producing excellent results, than you can try mixing up your own special plant food if you like. At least than you will know exactly what the problem is if things don't work out!

The same is true for using nutrient additives. Don't try to improve your results by adding a bunch of extra things to your nutrient reservoir (at least not at first). Start by feeding just the basic three part nutrients until your hydroponic gardening system is working smoothly and producing excellent results. Than if you like you can try adding vitamin B1, liquid seaweed, or silica (or all three).

Finally, you need to check and maintain your nutrient reservoir every day. After using the same nutrients for two weeks, you need to start over with fresh water and fresh nutrients. The most beneficial way to do this is to have two nutrient reservoirs, one with nutrient solution for your hydroponic gardening system and one with plain water for your next nutrient solution change. I can't stress how important this tip is! The second reservoir allows the water to dechlorinate and come to room temperature, both protecting your roots. See also my hydroponic nutrients page.

Root Health

If roots become damaged, they cannot take up nutrients to feed the plants. Any damage below ground will result in damage above ground as dead leaves and sick plants. Protect your roots by maintaining your nutrient solution properly, by using two hydroponic nutrient reservoirs (one with plain water for your next nutrient change), and by minimizing the amount of light that comes in contact with your nutrient solution. This will prevent algae, which will prevent fungus gnats, which will prevent root damage.

Adequate Lighting

There are very few shortcuts when it comes to lighting an indoor garden. You need a minimum of 40 watts/sq.ft., but 60 watts/sq.ft. would be better. Either high pressure sodium lights or metal halide lights will do a very fine job and are the most popular choices. For various reasons I recommend either a 600 watt light or a 1000 watt light. For help choosing a light, try my light selector tool. This will be one of your largest expenses- expect to pay between $400 and $600 dollars.

Regular fluorescent lights do not put out enough usable light for healthy growth and are only good for clones, seedlings, or very young plants in the vegetative stage. If you decide to go fluorescent, T5 lights (aka Tek lights) are really the only option. While T5 lights produce less heat than HID lights, they only yield about half as much. It is also neccesary to keep the tops of your plants within a few inches of the light, which becomes a real pain in the but.

Controling Temperature

HID lights put out a lot of heat, making temperature an issue in an indoor garden. Placing the ballast for your light outside the grow room will help, but it is not enough. A centrifugal fans or squirrel cage fans are an absolute must (see exhaust fan setup). In my experience, fans alone are often not enough. What is truely needed is a source of cool/cold air.

After years of organic and hydroponic gardening I have come up with only two solutions... plan to garden indoors whenever the temperature outdoors is 55*F or less. In this way you can pull cool, dry air into your garden as you exhaust the hot air. The only other option is to use air conditioning.

Photoperiod

Many crops require shorter daylight periods to trigger flowering/fruiting. Two keys to success here: First, the lights need to be turned off and back on at exactly the same time each day (tip- use a digital timer!). Second, the plants should be kept in absolute complete UNINTERRUPTED darkness during the dark period. Plants can be extremely sensitive to this, so don't try to skirt around this. For more info, check out my flower forcing page.

The Right Equipment/Tools

Don't start your garden unless you have all your bases covered from the beginning. You will need a completely dark area, a high powered fan, an adequate light, a hydroponic gardening system, hydroponic nutrients, an oscillating fan, a TDS meter (or EC meter), a pH test kit, and possibly an air conditioner. Minimum. A thermometer and a digital timer would come in handy too.

GROW LIGHTS FOR INDOOR GARDENT

There are many places where you can go wrong when it comes to garden grow lights for an indoor garden. The following advice will help you choose what grow lights to use, how best to use different lights, and some things to consider when using garden grow lights.

Skip this section and use the light selector tool.

Only three types of lights are really cut out for growing plants. They are fluorescent grow lights, metal halide (MH) grow lights, and high pressure sodium (HPS) grow lights. Any of these can be used as a garden grow light.

Light looses it's "punch" quickly as it travels away from the bulb, so you have to keep the plants within a certain distance from the light. This is especially true with fluorescent lights.

Fluorescent Grow Lights

In general, fluorescent grow lights are used for clones and seedlings. Fluorescent lights will not burn your plants, so plants can be placed as close to the light as you like. I usually keep the tops about 1 to 4 inches away. You may continue to use fluorescent grow lights for the vegetative stage, but you will need to use more of them to keep the growth nice and healthy. Plants grown under fluorescent lights usually do O.K. as long as you keep them no further than 18 inches away from the bulbs.

When it comes time to force flowering, plants grown this way must be given a few hours of high pressure sodium light each day for 3 or 4 days before they can handle the much brighter light (which is required for good fruiting/flowering).

Metal Halide Grow Lights

Metal halide garden grow lights are also used for the vegetative stage of plant growth. Plant tops under metal halide must be kept at least 12 to 18 inches away from the bulb or they will burn (especially in the hot spot!). It also partly depends on what size MH light you are using....plants will have to be kept farther away from a 1000 watt light than from a 400 watt light. Metal halide lights will support nice, healthy plant growth up to 24-36 inches tall, (depending on the size light you use), and they will reach this height much more quickly than with fluorescent lights. Plants do not need to be "broken in" to sodium light when they are grown first under metal halide light.

High Pressure Sodium Grow Lights

High pressure sodium High pressure sodium lights are used for the flowering stage of plant growth (to produce flower buds, fruits, and vegetables), although I have also used used Metal Halide lights for flowering with very good results. You must keep the plant tops at least 12 to 18 inches from these lights, or they will burn the plants. Once again, the distance away from the light will partly depend on the size light you are using.

Plants in the flowering stage require much more light to develop properly compared to the vegetative stage. Your garden should finish with well-developed fruits (or flowers) on the top 12 to 36 inches of your plants (and possibly more), depending on a several different factors... visit the different pages on lighting for more info.

Special Considerations

Before using indoor garden grow lights, you should consider a few things, such as...

The heat they produce

The electricity they use

How to be safe with both electricity and water in your garden

All these considerations will have an impact on your overall garden design, so it is very helpful to have your garden design plan (at least a rough idea) before you begin. 

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