Carbon Phix – THE BEST Carbon X Alternative

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Written By: Mark Marino, a Massachusetts Core Applicator License holder
and owner/operator of Lawn Phix,

No AI pledge. Authored and reviewed by Mark, not robots. Learn more.

Updated on


There’s no denying how effective and how well Carbon X fertilizer worked. It was a 24-0-4 blend with 14% sulfur, 7% carbon and 2% iron. Before Carbon Earth Company went out of business, Carbon X fertilizer was later re-labeled as CX DIY on Yard Mastery .

Since then, there has never been a true alternative… until now.

Formulated by Kelp4Less, we bring to you Carbon Phix – a real Carbon X substitute. Carbon Phix is a 20-0-12 granular lawn fertilizer blend that contains all of the major ingredients as Carbon X – minus the poultry litter – but spiked with their flagship granular Extreme Blend.

That’s right, Extreme Blend in every batch – essential L-amino acids, fulvic acid, soluble sea kelp, and extra humic acid to the tune of 5%!

The 20% Nitrogen is 60% fast-release, and the 12% Potash is SOP potassium sulfate. This new carbon fertilizer is derived from Urea, Ammonium Sulfate, Potassium Sulfate, Leonardite, and Iron.

IngredientCarbon XCarbon Phix
Humic Acid2%5%

Application Rates

At 3 lbs. per 1,000 sq. ft. Carbon Phix will deliver 0.6 lbs/ Nitrogen/1,000 sq. ft. Water in with 1/2″ of irrigation or rainfall to dissolve the fertilizer move into the soil. Apply every 4-6 weeks (more if spoon feeding).

  • 30 lbs = 10,000 sq. ft.
  • 20 lbs = 6,667 sq. ft.

Use our Nitrogen Calculator and Lawn Fertilizer Calculator to help with your specific needs.

Carbon Phix comes in a 20 lbs. or 30 lbs. box. Use coupon code lawnphix for 15% off your order and free shipping.

Carnon Phix vs Carbon X Comparison Table
Carbon X vs Carbon Phix
Carbon Phix Lawn Fertilizer
Carbon Phix – an all-new Carbon X alternative
Carbon Phix Lawn Fertilizer Bag Box
Carbon Phix Lawn Fertilizer in Spyker Spreader
Carbon Phix Lawn Fertilizer in Spyker Spreader 2

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Author's Note: this piece has been updated for accuracy since its first publication on

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Author: Mark Marino
My name is Mark Marino, and I am the founder, owner, and operator of Lawn Phix. With a passion for lawn care and turf nutrition for over a decade, I've dedicated countless hours to correcting soil and perfecting lawns. Today, my expertise, backed by formal courses at UMass Extension Pesticide Education, allows me to offer top-tier lawn care services and advice. I am a fully licensed and insured lawn care applicator in Massachusetts, specializing in comprehensive turf nutrition, weed control, and lawn pest control. My license number is AL-0053865. Contact me at [email protected] or +1 (508) 500-8402.

7 thoughts on “Carbon Phix – THE BEST Carbon X Alternative”

  1. About to order some of this, but I’m curious what the spreader settings are for it. If it helps, I will be using a Scott’s EdgeGuard Mini broadcast spreader.

    Looking at your Personal 2021 Plan spreadsheet, it looks like you’ll be applying it at a 4lb/1000 sq ft rate early on, then 2lb/1000 sq ft later in the year.. I assume this will just be different walking paces and not by changing the spreader settings?

    Looking forward to trying out Kelp4less products on my lawn this year, with your site for guidance! Appreciate all the hard work — keep it up!

    • Hi Jeremy – I don’t have the spreader settings other than my Spyker, which was about 5.5. I’m applying more Carbon Phix in the spring to put down more Nitrogen. In the fall, I’m spoon feeding after I overseed – so a little less Nitrogen per app but more frequent apps.

      Thanks for checking out the site and trying these products. I applied Carbon Phix and Heavy Hitter on a test spot last week and it’s already dark blue green. I think you’ll have great results, too! Let me know if you have any questions throughout the season.

      • Thanks, Mark! I’ll contact Kelp4less before I apply just to see if they have any recommendations on their spreader settings. If not, I’ll see if I can find somewhere that compares Spyker to Scott’s spreaders. That 5.5 should help me narrow it down, at least! Thanks for the explanation on application rates, too!

        I can’t wait to see how everything works out. Based on LawnPhix and Kelp4less recommendations, I’m going to try 4 different products in a rotation this season – Aeration + Yucca, Green Lawn & Turf, Carbon Phix and Extreme Blend. Hopefully my lawn will fill in nicely and choke out the remainder of the weeds I can’t seem to get rid of! I’d love to have a fully dark green lawn without any of that lime green ruining the view 😉

        Best of luck this season! I’ll be sure to reach out with any other questions.

        • Hey Jeremy. If you’re interested in Extreme Blend and Green Lawn & Turf, I’d choose one or the other. Green Lawn & Turf (GLT) is Extreme Blend but with the addition of molasses, iron, and extra Humic.

          I’d go with GLT and Heavy Hitter (and your Carbon Phix and Aeration + Yucca). Heavy Hitter has some Humic but has nitrogen and sulfur which is going to provide a great green-up “pop”. It also has some SOP.

          Let me know if this make sense.

          • Darn! I wish I would’ve consulted with you before placing my order. I spoke with two consultants at Kelp4less and they both recommended the Extreme Blend over the Heavy Hitter, and just recommended hitting them separately on 1/3 or 2/4 (weeks of the month), and then Carbon Phix/Aeration + Yucca on the opposite weeks.

            I think the 35lb bag of Carbon Phix will only be enough for 2 applications for me (so 2 months, based on your calendar), so I figured I’d start with these 4 and adjust when I reorder in May/early June. I’m already a bit skeptical I’ll be able to keep up with 1 product per week, so I’m all ears for a better approach. I would’ve followed your calendar to a T, but 1) I didn’t know that I wanted to go full-in on 7 different products in their lineup my first go-round, and 2) after speaking directly with Kelp4less, they recommended more of a “shotgun approach”, since the four they recommended pretty much covered most bases (including most of what you get with Thatch Eater, apparently).

            I think there was some confusion on whether or not/how much Extreme Blend was included in the Green Lawn & Turf and especially Carbon Phix (since it’s such a new product, they weren’t as familiar with exactly what all was included and at what amount). I even quoted this article while I was on the phone with them and they said they’d have to look more into it and may even reach out to you to clarify some stuff. From what the first rep told me, since the Extreme Blend I ordered is the soluble type vs the granular time-release (like in the Carbon Phix, supposedly? Maybe?), I can apply it much more often, so it wouldn’t hurt to apply it a few weeks after the Carbon Phix to give an extra boost. I asked if I should substitute Heavy Hitter or another product, especially after overseeding this fall and was told that wasn’t necessary.

            If there’s a complaint I have this early in the process, it’s that the plethora of products offered gets a bit confusing for newbies like myself, to the point where I almost didn’t order anything at all. Add to it that some of the mixes overlap other mixes and it almost becomes information overload. If it weren’t for sites like your guys’, and Kelp4less’s awesome customer service, I think all of us beginner/intermediate level guys would be completely lost and just stick with stuff like N-EXT lineups. I’m very thankful to have some info to lean on to try and clear up some of the confusion! Clearly I still have some room for improvement…

  2. So Jeremy, did you by chance also get an answer from them (kelp4less) on the spreader setting that you might share? I am using the exact same Scott’s edge-guard broadcast rotary spreder as you are! I just ordered some Carbon Phix to try! Thx.


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