Here you will find some basic questions and answers to get you started in the right direction with cultivation of your cannabis crop.
What do you suggest for Pest control in your garden?
A quick and easy way to control pest in your In-Door Garden, is to use a product called HOT SHOTS – No Pest Strips, which you can pick up at Home Depot. These strips put out a vapor that finds its way into every nook and cranny in your room, and kills pests quickly. They are recommended for Attics, Garages, Storage Spaces and other Non-Living Space. Its recommended that you dont spend more than 3-4 hours in the room with these pest strips, so simply putting them into a Plastic Zip Lock Baggie when they are not needed is the safest way to go, and then you can always pull them out for use again if pests return.
We have seen personally how well these strips work with killing Spider Mites and Fungus Gnats, and I would highly suggest using one in your grow room from time to time.
Be sure to also spread some diatomaceous earth around your grow area. Here is some Wikipedia information about its use as a Pesticide::
Diatomite is used as an insecticide, due to its abrasive and physico-sorptive properties. The fine powder absorbs lipids from the waxy outer layer of insects’ exoskeletons, causing them to dehydrate. Arthropods die as a result of the water pressure deficiency, based onFick’s law of diffusion. This also works against gastropods and is commonly employed in gardening to defeat slugs. However, since slugs inhabit humid environments, efficacy is very low. It is sometimes mixed with an attractant or other additives to increase its effectiveness. Medical-grade diatomite is sometimes used to de-worm both animals and humans, with questionable efficacy. It is commonly used in lieu of boric acid, and can be used to help control and possibly eliminate bed bug, house dust mite, cockroach, ant and fleainfestations. This material has wide application for insect control in grain storage.
In order to be effective as an insecticide, diatomaceous earth must be uncalcinated (i.e., it must not be heat-treated prior to application) and have a mean particle size below about 12 µm (i.e., food-grade— see below).
Although considered to be relatively low-risk, pesticides containing diatomaceous earth are not exempt from regulation in the United States under the Federal Insecticide, Fungicide, and Rodenticide Act and must be registered with the Environmental Protection Agency.
What is the proper PH for my grow?
The correct PH range for Hydroponics is 5.5-6.0 with 5.8 being the Sweet-Spot,, When growing in soil, then 6.5 is your Sweet-Spot. At 5.8 (in hydro) the plant is able to take up the most micro and macro nutrients without locking out important elements needed by your plants in order to thrive.
What kind of light do I need to grow cannabis?
During the vegetative period you will want to use Florescent or Metal Halide lighting in the 6500 K range. This will provide the Blue lighting the plant needs for building its stem and leaves structure.
Once your plant has grown to the height you are looking for, change the lighting to a High Pressure Sodium lamp in the 2400K range. These bulbs will provide the Red lighting the plants will need to produce flowers.
Standard bulb sizes are 250w, 400w, 600w and 1000w.
When do I harvest my crop?
This will depend on the strain you are growing, but a good rule of thumb is to use a 30x’s pocket microscope and check the flowers directly. You will look at the Trichomes and judge when to cut your plants down. Most people will wait for a mixture of Cloudy to Amber colored Trichomes. If you leave the plant to ripen longer, more and more of the Trichomes will turn an Amber color, and will also provide for a more Couch-lock effect, where cutting the plant while you still have more Cloudy Trichomes will give a more Heady type of effect.
What medium to you start your clones in?
We have found the best medium for us to use when starting clones are ROOT RIOT cubes.
Root Riot™ Plant Starter Cubes are specially inoculated with both micro-nutrients, which help to nourish the young seedlings, and beneficial rooting fungi, which naturally aids the root development process in young plants.
In short, you can’t go wrong by starting your seeds or sticking your cuttings in Root Riot™ Plant Starter Cubes!
Do you need CalMag in your RO water?
It will depend on the nutrients you are using, but in most cases RO water will require that you add CalMag to it in order to avoid the normal Calcium or Magnesium Deficiencies. This will also be dependent onthe Base Nutrients you are using, and whether or not those supply the proper amount of Calcium and Magnesium without the need to supplement. For example, CNS17 for Soil & Coco requires no need for the addition of CalMag.
What kind of containers should I use?
This will depend on how you are growing, but if you intend to grow with Hydroponics or Hempy buckets, then we strongly suggest you start your grow using Food Grade buckets, as many other buckets and containers on the market can leach some pretty nasty things into your feed.
How high should my humidity be?
If you are in veg, than you will want your humidity to be in the 50%-70% range, and you want to drop that down to 30%-50% while in Flower. A good way to keep control of your humidity is with the use of Oscillating fans. Air movement will help to lower humidity and also help fend off mold. We strongly suggest the use of at least 3 small fans in every flower room, cause air movement is Vital!
How long before I harvest my crop?
Most Indica strains will take 8-10 weeks once pre-flowers show, and Sativa strains can take 12-14 weeks to complete their flowering, and be ripe enough to harvest. This is one of the reasons why Indica’s are preferred for the indoor grower, not only do they finish faster, but also tend to stay on the shorter, smaller side of the growing scale.
What nutrients are best to use for my crop?
That’s not an easy question to answer, there are so many on the market today, you just have to try them for yourselves. We like the General Hydroponics Flora Series 3 part, and simply follow the bottle formula, but adjust it to the PPM’s we want, so we dont burn our plants.
We suggest starting your feeding out with a Low PPM like 200, and working your way up from there. Remember its easier to add more, than take away after the damage has already been done.
Nutrient deficiency chart?
PPM Conversion chart?
pH is measured on a scale from 1.0 to 14.0. Pure water has a pH of 7.0 and is considered pH neutral. pH below 7.0 is considered to be acidic and pH higher than 7.0 is considered to be alkaline.
A substance that decreases pH (pH-down) is called an acid while a substance that increases pH (pH-up) is called a base. A substance that helps nutrient solutions resist pH changes when an acid or base is added, is called a buffer.
A pH difference of 1.0 is equal to a ten times increase or decrease in pH. That is, a nutrient solution with a pH of 6.0 is ten times as acidic as a nutrient solution with a pH of 7.0. A pH difference of 2.0 is equal to a hundred times increase or decrease in pH.
It is very important to keep the pH level within certain limits when growing marijuana. Even first time marijuana growers need to monitor the pH of their nutrient solution or soil and keep it within optimum levels.
The pH level of your hydroponic nutrient solution or soil will determine how well your plants are able to absorb nutrients. If the pH level is out of the proper range, the growth rate of the plants will slow down or stop.
“Checking The pH Level Of Marijuana”
There are several means of checking the pH level of your hydroponic or soil garden. See this for information about obtaining pH measuring and adjusting equipment.
— pH Meter: used to measure the pH of water, hydroponic nutrient solution, hydroponic media, and soil.
— pH Test Kit: used to measure the pH of liquids like water or hydroponic nutrient solution.
— Soil pH Meter: used to measure the pH of soil.
— Soil Test Kit: used to measure the pH, nitrogen, phosphorus and potassium levels of soil. There are also soil pH test kits available that just measure the pH level of soil.
First time hydroponic marijuana growers should get a simple pH test kit to check pH levels. They are cheap, easy to use, and can be used multiple times. However, you will eventually run out of pH test liquid and have to buy a new kit.
They work by putting a small amount of nutrient solution in a container then adding a few drops of pH test liquid and mixing them together. The combined mixture will turn color. This color is then matched with the color on a pH chart (included with the test kit) to determine the pH level of the nutrient solution.
A pH meter can be used to measure the pH of water, hydroponic nutrient solution, hydroponic media, and soil. If you have been growing hydroponic marijuana for a few years and you are tired of buying and re-buying test kits, it might be best to invest in a pH meter.
A pH meter is long lasting, and in general they give more accurate results than other methods of measuring pH. But the price may make them out of reach for first time growers on a budget. They also have probes and batteries that eventually will need to be replaced.
For accurate measurements always follow the manufactures instructions for calibrating, cleaning, and using a pH meter. Calibrating the meter is especially important because all measurements will be wrong if the unit is mis-calibrated.
Because pH meters can measure the pH of water, hydroponic nutrient solution, hydroponic media, and soil they are strongly recommended for growers who use hydroponics to grow indoors and soil to grow outdoors.
Soil growers should get a soil pH meter to measure the pH level of soil in their garden. They work by inserting the probes of the unit directly into the soil you are growing in, and taking a reading. Follow the manufacturers instructions included with the soil pH meter you use, and you will get years of accurate measurements.
An alternative for soil growers is a soil test kit. These are easy to use and reliable kits that contain separate tests for pH, nitrogen, phosphorus, and potassium. They give instant results on the soil conditions in your garden.
A single soil test kit will have a certain number of tests that can be preformed before you run out and have to buy another. For example, one company makes a soil test kit that can be used to check pH, nitrogen, phosphorus, and potassium levels in soil 10 times.
“pH And Hydroponic Marijuana”
When growing hydroponic marijuana the pH of the nutrient solution should be between 5.5 and 6.8. In most cases optimal pH is about 5.8 to 6.3 but this may vary slightly depending on the particular marijuana strain and the growing conditions you provide.
Some growers report good results with pH as low as 5.0. You can experiment to see what works best for your particular plants but always keep the pH between 5.0 and 7.0.
Measure the pH right after you add the nutrient solution to the reservoir (mix well first) because the nutrients will change the pH level of the water. Check the pH level about once a week.
“Adjusting pH of Hydroponic Setup”
pH-up and pH-down solutions are used to adjust the pH level of hydroponic nutrient solution and hydroponic media when the pH is out of range. pH-up (also called pH increase) is used to raise the pH level and pH-down (also called pH decrease) is used to reduce the pH level. A pH-up or pH-down solution for hydroponic or aquarium use is recommended.
For hydroponic applications, nitric, phosphoric or citric acids (even vinegar) can be used to lower pH, while potassium hydroxide can be used to raise pH. If you understand what you are doing, you can use them instead of buying pH-up and pH-down solutions (contributed by james and jorge).
However, if you aren’t sure of the correct amount of acid or base that is needed to adjust the pH to optimum values, it is best to buy a solution specifically made to raise or lower the pH and carefully follow the manufacturers instructions.
Unless directed to do so by the manufacturer, don’t try to adjust your pH by more than 0.2 per day. Make drastic changes over a number of days. If your pH is 7.0 and you would like it at 6.5, try lowering it by 0.1 a day for 5 days (or do it even more gradually). Overcompensating can spell disaster for your garden.
“pH And Marijuana Growing In Soil”
When growing marijuana in soil the pH of the soil should be between 6.5 and 7.0. When growing in containers, a single pH reading for each container is recommended. When growing outdoors in a garden, it is best to take two or three pH measurements from different areas of the garden.
If you have a large garden, you may have to adjust the pH in various parts of your garden to different levels. Check the pH once every one-two weeks.
Unlike hydroponics where the nutrient solution is in a single reservoir and only needs to be checked once, a soil garden will get its nutrients from the soil it is growing in. Even a small garden that contains a few plants may have soil that varies in pH from one area to another.
Most fertilizers cause a pH change in the soil. Adding fertilizer to the soil almost always results in a more acidic (lower) pH. As time goes on, the amount of salts produced by the breakdown of fertilizers in the soil causes the soil to become increasingly acidic and eventually the concentration of these salts in the soil will stunt the plant and cause browning out of the foliage.
Also, as the plant gets older its roots become less effective in bringing food to the leaves. To avoid the accumulation of these salts in your soil and to ensure that your plant is getting all of the food it needs, you can begin leaf feeding your plant at the age of about 1.5 months.
Dissolve the fertilizer in water (worm castings mixed with water will work well for leaf feeding) and spray the mixture directly onto the foliage. The leaves absorb the fertilizer into their veins. If you want to continue to put fertilizer into the soil as well as leaf feeding, be sure not to overdose your plants.
“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.
TDS and pH Explained
We all know that plants, whether they are growing in a hydroponic system or a soil system, require nutrients. But choosing the right nutrient formula is just the first step. Maintaining the proper nutrient strength can have a substantial impact on plant performance; therefore any serious grower should have a TDS or EC meter available. Even after adjusting the strength of the nutrient solution to meet the plant’s needs, the nutrients still may not be available to the plant if the pH is not is not within the proper range. Thus, a pH meter is a vital piece of equipment that should be a part of every growers arsenal. In this month’s article we are going to take a closer look at TDS, pH, and the meters that are used to measure the nutrient solution.
What is TDS/PPM/EC
Firstly, TDS (or Total Dissolved Solids) is measured in units of PPM (or Parts Per Million). EC (or Electrical Conductivity) is measured in either µS (MicroSiemens) or mS (MilliSiemens). In the USA we use PPM and internationally µS and mS are the preferred measurements. Both TDS and EC meters measure nutrient strength in the same way with the same accuracy; however the readouts are displayed differently. For example: a nutrient solution that measures 1000ppm, on a TDS meter, will be the same strength as a solution that reads 1430 µS or 1.43 mS on an EC meter.
TDS and EC meters measure the strength of a nutrient solution by measuring the flow of electrical current between two metallic probes. The higher the salt concentration in the nutrient solution the better it conducts electricity; therefore the higher the reading on the meter. It is extremely important that the batteries are in good, strong condition and the probes must always be clean from salt deposits. Weak and dirty probes will effect the accuracy of the reading and are the biggest causes of inaccurate readings.
PPM Conversion Factors
Not all TDS meters will give the same PPM reading. The main reason for this is that different meters will use different conversion factors. These conversion factors are based off the EC reading. For example: A meter that uses a conversion factor of 0.5 will display a reading of 0.5 times that of the EC reading. If the EC reading is 1000 µS then the ppm reading will be 500 ppm. It is as simple as multiplying 1000 by the conversion factor of 0.5. If the meter uses a conversion factor of 0.7 (the most common conversion factor used) then 1000 µS would be 700 ppm (1000 x 0.7). When purchasing a TDS meter it is very important to find out what the correct conversion factor is for the meter. It could make a difference of more than 200 ppm! Not only is it important to know what the conversion factor for the meter is, it is also important to know the conversion factor of the calibration solution. Generally speaking, Genesis calibration solutions are for meters that use a 0.7 conversion factor and the Hanna solutions are for meters with a 0.5 conversion factor.
0.5 conversion 0.7 conversion Adjustable conversion
– Hanna Primo – Hanna HI 9813-0 – Hanna HI98129
– Tri-Meter – Hanna HI 9813-6 – Hanna HI98311
– Hanna HI981504 – Hanna HI 983301N – Hanna HI981404
– Hanna HI 983311
(no calibration required) – Hanna HI981404N
– Blue Lab Truncheon TDS/EC (displays reading in PPM (0.5 and 0.7) and ECM
– Oakton Meters