Save Money: Mix up a Bulk Batch of Complete Organic Fertilizer (COF)

Want to save money on your organic fertilizer expense? Have you tried mixing up your own bulk batch of complete organic fertilizer? It is easier than you would think.

(This post is not sponsored, but it does contain affiliate links in case you like what we recommend. See below for more details.)

Every year since making the switch to organic, we try to shave a little off our gardening expense by mixing up our own bulk batch of ‘Complete Organic Fertilizer’ or COF. Once you have your ingredients together it only takes a few minutes and is so nice to have on hand for the gardening season. One batch based on a fifty-pound bag of cottonseed meal produces roughly two five gallon buckets of complete organic fertilizer that lasts me two gardening seasons, give or take. As long as you keep it dry, it keeps indefinitely.

The recipe is based on the one found in Steve Solomon’s book, Growing Vegetables West of the Cascades: The Complete Guide to Organic Gardening. This book is a must read for every Pacific Northwest organic gardener. It has served as my organic gardening bible since we made the switch away from agrochemicals four years ago. Not just for me, this is the main fertilizer used by the Master Gardeners and what they sell a pound or two at a time at our annual plant sale.

Here is what goes into it

All measurements are by volume (scoop, bucket, shovel, etc)

Note: The original recipe uses 4 parts seed meal and half parts of the remaining ingredients. I find that starting with 8 parts just makes the math easier.

Where to Buy the Ingredients

There are links above where you could order the ingredients online, but in most cases you will save money by buying your ingredients locally.

Start by contacting your local feed store to order the cottonseed meal. This is the only way I have been able to get it. I get fifty pounds for $29. This is the only ingredient that I need to buy every year. You use such relatively small amounts of the other ingredients that if you buy those in bulk and keep them dry, they will last you a while.

Dolomite lime is easy to get your hands on, but I had to ask around a bit for the ag lime. If you can’t find it, or don’t want to bother, you can skip it. Just use a full part of dolomite.

A couple of years ago I invested in a large bag of kelp to further cut down our costs. I store it in a five-gallon bucket with a lid and keep it dry. I will be pulling from that bucket for years to come. Kelp tends to be the spendy part, so you can also buy it in a smaller box, just enough for your batch, but pound for pound you end up paying twice as much. Kelp is important because it supplies lots of minerals and micronutrients. This gives your plants what they need to stay strong and help with overwintering for us cool season gardeners.

Mix it up

If you have a patch of flat concrete and a straight edge shovel, this goes really quick. If you don’t have a patch of concrete you might use a tarp spread out on the ground. We do a pretty big batch. Of course, if you are mixing up a smaller batch you can use whatever works.

Measure out your ingredients by volume. Eight scoops of seed meal and one scoop each of the other ingredients.

Now, mix away! Keep mixing until you see that your ingredients are evenly dispersed.

Store it

Scoop up your batch into containers. I use five-gallon buckets for everything. You will want something with a lid to keep out the rodents. Otherwise, they will munch on this stuff and you will find your supply strangely dwindling. It is always good to keep your organic fertilizers in rodent-proof containers to prevent attracting unwanted pests.

Using your Complete Organic Fertilizer (COF)

The general guidelines are…

  • 1-2 gallons per 100 square feet
  • 1/4 – 1/2 cup per plant
  • 1 cup per 10 row feet

Use as much or as little as the plants will respond to.

For more detailed information about Steve’s recipe and how to use it, along with growing guides and tips for gardening west of the Cascades, grab the book.

Affiliate Disclosure

This is not a sponsored post, but it does contain affiliate links. Why? Because we actually use this stuff and think you will find it useful too. We will never share links or promote items that we don’t use ourselves. How lame would that be? We are here to share information and be helpful and one of the ways we like to do that is by pointing our readers to things that might improve their lives in one way or another. So, rest assured, you can trust that we have your best interest at heart. If you happen to click on a link and make a purchase, we do get a little compensation for referring you. This is one way we are compensated for the time it takes to put this blog together. The other is just the good feeling of helping out and connecting with like-minded folks. Otherwise, I would be out there gardening. 😉

Here is the full legal disclaimer…

PNW from Scratch is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to

Now that that is over with… back to the fun stuff.

Get out there and grow!

Check out this post to see what a garden fed with this fertilizer can look like:Going on in the PNW Vegetable Garden – September Photo Tour & Garden Journal

Share pictures of your garden on Twitter, Facebook, and Instagram… mention us or hashtag it #PNWfromScratch… we would love to see how your garden grows!

1 thoughts on “Save Money: Mix up a Bulk Batch of Complete Organic Fertilizer (COF)

  1. Pingback: [VIDEO] Seed Sprouting and Succession Planting with Arugula and Salad Greens - PNW from Scratch

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