Frequently Asked Questions

Growing Questions

When should I start feeding my plants Pure? If starting from seeds you should start about 2 weeks after germination a low EC and ramp up slowly. The seed itself has enough nutrients for about 2 weeks. If starting from clones you can start feeding as soon as the clones are rooted. Grower Tip! If using rockwool, or high quality coco those two substrates are inert, meaning they have no nutrients in them and you are the plants' only source of food. To avoid deficiencies early during the crop cycle ensure you are feeding them nutrients out of the gate.

How often should I feed my plants? We recommend you feed your plants at every watering during the growth cycle to avoid deficiencies. It's ok to give straight water once in a while if you find your growing media has a high EC (amount of nutrients in the soil) after doing a soil test. 

Do I need to use R/O water with Pure? Our recommended rates are not including the starting EC of your fresh water source. If you are using R/O water or your water has a very low TDS/EC you can count on the rates we recommend (grams per liter) to give you the listed EC on the bags. Tap water is normally below a TDS of 200PPM. If you have water with a high TDS/EC lower the amount of Pure accordingly.

Do I need to flush during the crop cycle? We highly recommend monitoring your soil by doing a leachate test to determine the nutrient content in your growing medium. Typically if the soil pH is in the proper range the roots take up almost all of the Pure nutrients being given. Keep an eye on the growing medium and if the EC is high consider giving straight water for a couple of waterings. See this great instruction on how to conduct a leachate pour through test - https://content.ces.ncsu.edu/monitoring-and-managing-ph-and-ec-using-the-pourthru-extraction-method

Do I need to flush at the end? This is an age old argument. The main difference between flushed and unflushed flower is in the ashes – you want it to burn as white as possible. The majority of people flush to eliminate built up nutrients in the flowers, but this leaves yield on the table you could otherwise have if you fed right to the end (up to 8%). Our opinion is that many nutrient lines do not use high quality inputs and they leave loads of sulfur and carbon behind. By using high quality food grade nutrients like Pure you may find the ash burns much whiter even when feeding right to harvest. We suggest trying a few plants with no flush and judging for yourself.

What should my target PPM be? In coco and soil it should be in the range of 700-900 for veg and 1000-1300 for flowering plants. We recommend 500-600 in DWC during Veg and 700-900 during flower. But again we stress each crop and strain is a little different, and it depends if all other growth factors are in good range such as light, temp, RH, CO2 etc. At the end of the day you have to be the judge and be able to listen to what your plants are telling you.

What is the difference between ppm (N) and ppm? Because we come from commercial horticulture we publish our numbers for fixed nitrogen concentration (ppm N). Most hobby nutrient companies just use total TDS/PPM. 150-200 PPM N is often recommended for cannabis crops for a constant feed rate. 

I notice you use EC and I am familiar with PPM. How do I convert between them? To obtain an approximate sodium chloride TDS value, multiply the EC reading (in milliSiemens/cm) by 1000 and divide by 2. To get an EC value, multiply the ppm reading by 2 and divide by 1000. 

Thus, if your EC is 1: 
1x1000/2 = 500 ppm. 


And if your ppm is 500: 
500x2/1000 = 1 EC 

Can I foliar feed with Pure? It should not be necessary to foliar feed with Pure, as the blends offer all the essential nutrients your plants will require as long as you are feeding your plants on a regular basis.

What pH should my nutrient be? For optimal nutrient uptake between 5.8 - 6.5. Check after mixing the Pure into your water.

What pH should my soil pH be? Cannabis plants prefer a slightly acidic environment for its roots. Growers using soil as their medium should adjust their pH to a range of 6 to 6.5. For a soilless garden, pH should sit between 6.0 to 6.5. Coco should be closer to the 5.5 - 6.0 range. To check your soil pH really fast and easy consider the Bluelab Pulse Meter found here!

Can I use Pure in coco, rockwool and in DWC? Yes! It was designed for using in any grow medium. We just suggest lowering your EC about 20% if growing in water (DWC)

Are Pure Nutrients organic? No, Pure nutrients are a synthetic blend of food grade fertilizer used by large scale commercial horticulture but it is not certified organic. Our CP-50 on the other hand is certified for organic production.

Do you test your products for heavy metals and pesticides? Yes! Every batch of Pure is 3rd party tested for heavy metals and pesticides. A copy of the latest lab reports are available on request.