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Frequently Asked Questions

  • Jack’s is for greenhouse grown crops – why now switch to cannabis?
    Our Jack’s research team gained so much knowledge of all different types of plants and growing environments over those years that we felt compelled to direct our formulation effects to address the nutrient interactions and uptake that we saw with cannabis in various grows.
  • Are Jack’s Nutrients Formulas different than other Jack’s products?
    Oh Yes! And that is what has taken so long. People often ask us why we waited to release this product line. We have spent years working with fabulous growers to tweak each idea of a formula to make sure it produces the results that are important when growing all different types of crops in a controlled environment.
  • Which Jack’s fertilizer(s) should I use to feed my cannabis plants?
    If you are using Rever osmosis water, rainwater, or distilled water – we recommend the 3-2-1 or the 12-4-16 program. If you are using well water or tap water, send a water sample to the JR Peters Laboratory for a full nutritional analysis. Once you receive the results via email you can send them to to get dialed in!
  • Why Jack's Nutrients versus other Jack's formulas?
    Our Jack’s Nutrients formulas are made with the same high quality raw materials you would expect from anything made by JR Peters Inc. However, the balance of nutrients are different than our tried and true greenhouse blends. There are so many ways to reconstruct a fertilizer formula – that is why you see MANY different versions of a 15-5-15 but when you look at the label they don’t match up. Our Scientists build our master crafted Jack’s Nutrients formulas with the consideration of when, how and why cannabis plants take up nutrients under different controlled and home environments. Plus, we designed optimized formulas in easy to understand and use packages. You don’t need to be a plant scientist to understand what formula to use. JR Peters has done that for you.
  • Looking for Jack's Mixology Tips?
    One of the most common fails when using a Part A and Part B system occurs during the mixing steps. How do you know what nutrients can go into what bucket? It seems quite simple, part A in its own bucket and part B in the other, but what about other additions and boosters? Certain nutrients in the fertilizer world just are not compatible with each other and when mixed in stronger concentrations they will precipitate. The most common culprits for these messy situations are Ca-P precipitate, when a high P formula is mixed with a high Ca formula (ie. Blossom Booster 10-30-20 with Calcium nitrate 15.5-0-0). Another very common one is when a grower attempts to add a nutrient boost from Epsom Salts. When Epsom salts (a Mg-S source) is mixed with a Ca source in concentration you will have just magically made yourself a very messy clump of Gypsum (a Ca-S source) in the bottom of your tank. Both of these mixing mistakes are quite common and I often say to growers, once you make this mess once, you will never do it again. Crunchy stuff at the bottom of the tank is NOT an indication that there is fertilizer in there, it is evidence of a precipitate that will not go back into solution.
  • I’ve grown in a traditional greenhouse before, how do I know what formula to start with for my specific grow?"
    We hear this type of thing a lot at the JR Peters Lab. It is probably no surprise to hear me say that it all does start with your water quality. A simple water analysis will act as a baseline, really giving you an idea of what you are starting with and what you may or may not have to add to the system to grow healthy plants. In both situations, we look at your water quality, but also consider the whole picture – the media type (soilless or hydroponic), the plant type you are growing, and your environment (controlled or traditional). That may seem like a lot, but just a conversation with our technical people about these things while looking at the lab analysis of your water will help steer us in a direction to tailor a fertility program just right for you.
  • Does Jack’s Nutrients work in hydroponic systems or only soil?
    Jack’s works wonders in hydroponic systems (DWC & RDWC), aeroponics, rockwool, coco, soil-less potting mix, and field soil.
  • Looking to use Jack’s Nutrients for Hemp?
    We have been really busy setting people up with nutrition programs to grow Hemp this year. If you are just looking for general recommendations without delving into the specifics through our Jack’s No-Brainer Program, many people are having success using these formulas in the different stages: Start - to build a healthy root system Jack’s 15-6-17 Clone Veg Jack’s 18-8-23 Outdoor a formula specifically for Outdoor production when the environment needs an acidic formula Jack’s 15-5-20 Tap - or a combination of the two - Flower Part A + Part B or Jack’s 10-30-20 Bloom or Jack’s 5-50-18 Ultra Violet or timed boosts of alternating schedules again matched to targets Finish Jack’s 7-15-30 Finish by itself or in combination with the other formulas
  • I like to really have control of things, how will the Part A/B system let me do that?"
    A lot of times we find that professional hydroponic growers value the option to be able to manipulate their nutritional inputs when things change. Growers become very attune to their growing environment and how it can affect plant growth rate. Changes in the environment can be due to many things, one of the most common is the light level either outside (time of year) or indoor light schedule. Light levels at either extreme can influence the plants transpiration rate. When there are lower light levels, for example, like during the 4th Nor’easter storm of the winter, the plants rate of transpiration slows and this goes hand in hand with reduced nutrient uptake. A grower using a A/B injection system can manipulate the ratio of nutrients very easily. In this case they could adjust the Part B injection rate while keeping the Part A concentration steady. This will give the plants a needed 30-40 ppm boost of Ca from the Part B while keeping the micronutrient concentration steady with a consistent Part A injection.
  • Do you ship to Canada?
    Currently we do not ship directly to Canada, but that doesn't mean you can't find us there! We're excited to have distribution partners in Canada that can help ou find the Jack's Nutrients that you're looking for. Eddi's Wholesale is one of those distribution partners. They can help you find stores in your local area already carrying Jack's. Here is the link to locate the stores in your area based on your postal code:
  • Do you have any Europe distribution?
    Unfortutnely, we do not have any distribution outside of the US & Canada. Keep an eye out on our here and our Instagram page @jacksnutrients for updates. If you're an international distributor in Europe or elsewhere interested in carrying Jack's, let's have a conversation. Email to talk!
  • How can I get my water tested?
    Here at Jack’s we love that you are interested in getting your water checked out. Check out THE LAB section, here you will see to buttons to download the water submission form and how to take a sample. Once our lab crew receives the sample you will be alerted via email and should have the results within 24 – 48 hours! If you have any questions in the meantime, do not hesitate to ask.
  • Can I get a sample of your products?
    Currently we do not have any samples, however, our KITS are a great way to try a specific growing program, like City Limits, Pure & Simple or Jack's 3-2-1.
  • HELP... what to use for my grow?!
    WELL, let us start by saying… it really depends on a number of factors, BUT we suggest checking out the Tech Stuff. This will help to give you an overview of a few suggested feed schedules and what products we recommend depending on how you are growing. You will find lots of great info on how to use our Jack’s 3-2-1 program as well as where to find the products. We are super excited that you are looking to give our Jack’s Blue a try, so if you would really like to get down and dirty and have our crew start from the ground up with customized recommendation just for you check out our Jack’s No-Brainer program. As we mentioned, there are many steps to finding the right match of fertilizer and nutrient formulas for your facility and the team at Jack’s has over 72 years of experience in the process. Our Jack’s No Brainer is a program designed to help everyone customize their own nutrient plan as well as receive important materials and tips to help grow the highest quality crop using Jack’s fertilizers. If you have a moment, check out the program - it will explain the steps and what to expect during this process.
  • Do you have any current coupon codes?
    Sorry we do not have a coupon code at this time. Keep an eye out on our website and our Instagram page @jacksnutrients for updates.

Want to find out more about Jack's Nutrients? How to grow with Jack's? Or where you can purchase our products. The Answers to these and more can be found below.

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