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 ccaporaso@jrpeters.com to get dialed in!

How do I send a water sample to the JR Peters Lab?

Click on this link JR Peters Laboratory – here you can request a water test kit, which comes with two water sample bottles, an envelope to send the sample back, and instructions on how to send a water sample in.

Does Jack’s 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.

What should my pH be when using Jack’s?

For hydroponics, coco, and rockwool – we recommend a pH range of 5.5-6.0.

For field soil or soil-less media (potting soil) – we recommend a pH range of 6.0-6.5.

How often should I feed my plants?

We recommend feeding every time you water your plants as a CLF (Continuous Liquid Feed Program) which provides a continuous low rate of nutrients throughout the grow.

I am growing in soil; how often should I water my plants?

We recommend waiting until the first two inches of soil are “paper bag brown” dry, before watering again. And of course, feed every time you water!

How long should I use the 15-6-17 Clone formula?

We recommend using the 15-6-17 Clone formula on clones or young seedlings for the first 2-3 weeks, until they have 3-4 sets of true leaves. After those 2-3 weeks are up, begin using a base formula (3-2-1, 12-4-16, 15-5-20, or 18-8-23) and watch those babies grow!

Why only use the 10-30-20 Bloom for 1-2 weeks?

The 10-30-20 Bloom was designed to be used for 1-2 weeks. This formula will be pump Phosphorus into your plants, creating a smooth transition into flower. Side note: 10-30-20 Bloom does not have Calcium in it, so after those 1-2 weeks are up – switch back to your base formula (3-2-1, 12-4-16, 15-5-20) to give back the Calcium that cannabis crave!

What does the 7-15-30 Finish do and how long should I use it?

The 7-15-30 Finish is loaded with Potassium which goes right to the buds resulting in some fat colas!! Use the 7-15-30 Finish, the last 1-2 weeks before flush/harvest and help fatten those buds up!

Why use a veg formula in flower?

Through scientific studies and working with our cannabis trial growers, we found out that cannabis still likes a good amount of Nitrogen during flower! Plus, our grow formulas (3-2-1, 12-4-16, 15-5-20, 18-8-23) still have a solid amount of P and K, which is essential for bud development.

What supplements should I add to Jack’s?

We got you covered on the essential nutrients! No need for supplements such as Cal-Mag or PK boosters. Some growers are adding Microbials and Silica with great results, while other growers only using Jack’s have great results too!

Should I flush my plants when using Jack’s?

We recommend flushing your plants if the salts are building up in the rootzone (high runoff EC/ppm) or flushing with clear water 4-7 days before you harvest. (That is if you believe in flushing – we know there is a big debate!)

I am using city tap water or well water and my ppm’s are coming out at 150-250 ppm’s. Which Jack’s formula should I go with?

Since you are using tap or well water, send a water sample into the JR Peters Laboratory for a full nutritional analysis. This way, we can see everything in your water (nutrient wise) and get you dialed in right off the bat! Once you receive the results, send them to ccaporaso@jrpeters.com and Cody will dial you in! If you do not want to go the water test route, use the 3-2-1 program, as this program provides growers with the most flexibility, due to the 2-bag base system (Part A 5-12-26 & Part B 15-0-0).

Can I use Jack’s as a foliar spray?

Yes, you can but it is not the best way to feed your plants when using Jack’s! There are tiny pores and stomata on the leaves that only allow so many nutrients in. You will get the most out of Jack’s when you apply our fertilizers directly to the rootzone.

Do I need to adjust my pH when using Jack’s?

Our formulas were designed to cause an initial acidic reaction. However, it depends on how much alkalinity you have in the source water you are using. If you are using RO or distilled water, most likely there is very little to zero alkalinity. This can cause the pH to fluctuate. So, you may need to add pH down or a mineral acid to lower the pH and some may need to add pH up or Potassium Bicarbonate to raise the pH. First mix and dissolve the nutrients completely, test the pH and adjust up or down from there (if needed)!