Is 10-10-10 Fertilizer Really The Best Garden Choice?

10-10-10 Fertilizer

10-10-10 fertilizer is certainly one of the most popular fertilizers. This week, I received a great question about the nutritional difference between it and compost:

Most bags of compost and manure say they have about .1-.1-.1 of the big 3. I have tested my own compost and it is somewhat higher but still not in the 10 10 10 range recommended for most plants. So, how do you get enough without using fertilizers? Is 10-10-10 the same as .1-.1-.1? Am I missing something?

I’m really glad you asked. There are 3 things I’d like to address…

1. Fertilizer Labels

In many countries, in order to be considered a fertilizer, a product must contain a minimum percentage of total nitrogen, available phosphate and soluble potash.

That’s often written as NPK – such as 10 10 10 fertilizer or 5-10-5 fertilizer – “the big 3” mentioned in the question above. That required percentage can be quite high, well over 20%.

Notice that it’s available phosphate and soluble potash, not total. This has an unfortunate consequence for organic fertilizers.

Nutrients in organic fertilizers are wrapped up in various organic compounds that need to be broken down by microbes before they become available to plants.

That’s how nature does it, and it takes time. Most of these nutrients are not so quickly “available.”

That means much of the NPK in these fertilizers doesn’t get counted on the label, which means many fertilizers used in organic gardening don’t qualify as a fertilizer, and look like poor value when compared to the high numbers of a chemical fertilizer.

They may be sold as soil amendments or perhaps specialty fertilizers, with low NPK numbers.

That’s why things like compost and kelp aren’t technically “fertilizers.” For example, the seaweed fertilizer I use is only a 0-0-1.

2. What Is A Complete Fertilizer?

Further, the law says a “complete fertilizer” only has to supply these three nutrients. We know, of course, that plants need many dozens of nutrients (perhaps over 70), so it makes no sense to apply only three.

In fact, applying too much of these three indiscriminately often causes more problems than benefits.

As we’ll see below, while we need a lot of different nutrients in our soil, we don’t need all that much of any of them.

That’s one reason why quality compost and biostimulants like sea minerals are often the best garden fertilizer choices – they supply everything in tiny amounts, just to make sure all of the nutrients are covered.

3. How Much Of Each Nutrient Does A Plant Need?

Now, onto your specific questions. 10 10 10 fertilizer is not the same as .1-.1-.1. It contains 100 times more total nitrogen, available phosphate and soluble potash.

And when you mentioned that you’re compost doesn’t reach the “10-10-10 range recommended for most plants,” the fact is that this big range is recommended for the profits of the manufacturers, not for the health of the plants.

You asked how to get enough nutrients without using fertilizers, and the heart of the question is really, “how much of each nutrient does a plant need?”

The answer is shockingly little. Only tiny amounts of each nutrient are actually removed from the soil when we harvest the vegetable garden. We’re talking grams of each nutrient.

If our soil is poor and losing nutrients through leaching and volatization, we need to add a little more than if we have a balanced, sustainable ecosystem, but not nearly as much as one might think.

We do still fertilize, but mostly for different reasons (I’ll save that for another article).

10-10-10 Fertilizer Summary

The bottom line is:

  • Fertilizer labels are very misleading, implying that plants need high amounts of just NPK – plants need many more nutrients than NPK, and they need very small amounts of each.
  • The chance that your plants and soil will be happy with 10-10-10 fertilizer is very low – plants prefer their nutrients in organic form, prepared by microbes.
  • Well-made compost and biostimulants are some of the best fertilizer choices for supplying what plants really need.
  • Sometimes it does make sense to use tiny amounts of N-P-K fertilizer, as I discuss here.

Any questions or comments about 10-10-10 fertilizer? Let me know below.

32 Comments

  1. yardenlb on April 28, 2012 at 10:53 pm

    So are we to focus on feeding the microbes in the soil so that they can do their work in feeding our plants?

    • Barry hocking on April 29, 2012 at 2:55 am

       Yep true feed the soil not the plants. Different plants have different requirements.

  2. Djejenkins on April 29, 2012 at 3:28 pm

    Thanks for answering my question! Very enlightening

  3. Africanaussie on April 29, 2012 at 11:15 pm

    I was just adding compost , fresh seaweed etc to the garden, but felt there was not enough fruiting a flowering.  Lately I am adding just a touch of sulphate of potash to a foliar feed every couple of weeks and have noticed a marked improvement.  Also trace elements seem to be lacking in our soils.   We have such high rainfall during the wet season that i think these need to be replaced now at the beginning of the dry season.  I am thinking that each area is different and the longer you live in an area the more you understand each particular area.   Definitely agree with little bits of everything more often, and then see how things go before adding more..

    • Phil on May 5, 2012 at 4:43 pm

      That’s interesting – I wonder why the sulphate of potash is encouraging flowering/fruiting. Perhaps you’re low in sulphur or potash or maybe it’s just the energy boost they need.

  4. lawrosa1 on May 2, 2012 at 5:59 pm

    Hey Phil,So here in the states, NJ to be specific, the gardening season is cranking along. I only started my 1000 sq ft garden this year. Tilled up my lawn and left all the chopped up grass in there. I thought I would have soil issues but I guess not. i did pick out large grass clumps and have a compost pile going.So no tests on the soil and am just winging it. I did get out of your site the mycorrhizae concept, and gardening all organic.So I wish to show you what I feel is good for being all organic, and please critique as needed.First off here is what I have so far.I have a identical plot on the backside yard with the same dimensions. You can see I added irrigation risers for watering. Coming from the well with a PH of the water at about a 6.0. There is nothing I can do about that.You see I have lettuce, cabbage, celery already growing good. I have had several salads already and am following a continuous harvest plan. I just transplanted the tomato’s and peppers, more celery and parsley. Beets and carrots are growing good, and chard is just sprouting.Now what I use? And this is all I have been doing 100%I have been using this to prep the soil before seeding and transplants.Dr Earth. 5 7 3 ( No GMO, sewer sludge, or poultry manures. Has mycorrhizae in all his products.I sprikle it on the soil and rack it in the top 4″ I only pitch fork the soil and lift it for aeration. ( There are many worms in the soil and I though from me tilling these section hat I messed up the soil. I have been also spraying this at the recommended 1 oz per gallon as a foliage and soil drench every two weeks or so. As far as pesticides and fungicides I have not had any issues yet except for my apple tree with Caterpillar, and my beets may have a fungus because of leave spots. Some cabbage leaves have also had some worm/Caterpillar damage.I use this. Organocide OMRI approved. I used the 3 in 1 and worm and Caterpillar.I did use the mycostim during my first plantings but the stuff was $$$ and I thought it was better to get the DR earth stuff that has it in it and is a fertilizers.Oil based products. So from what I learned from your site is feed a little at a time is better then a lot at once. I believe I am feeding properly because everything is growing fine.What do you think of the products I use and how I am applying Them?Any advice you can give would be appreciated.Also no offense Phil but your academy is a bit pricey for a per month bases. I am not sure what you are offering in addition to what you already have on your site but it does not seem cost effective. Possibly a yearly membership at $70 usd would be more in line. people dont want monthy bills with this economy like it is and need some kind of value for thier money.Just my opinion.A smart guy like you should venture into what this lady is doing in my area. She gets $45 an hour for consulting from what I hear. She has other packaged where she will set up your garden for you and teach you every step of the way.She comes to your house with raised beds and such and gets you going. OK Phil thank you for helping me and I hope I may have helped you in return somewhat.Regards,Mike L. New Jersey USA

    • Phil on May 5, 2012 at 4:41 pm

      Hi Mike, seems like you have a good start there. A mulch layer would be your friend. I only comment on specific products for Academy members, because it takes some research on my end to figure out if a product is good. It seems you’re on the right track – the success rate will depend on the balance of nutrients in your soil (especially calcium) and the humus. I’m not a huge fan of BTK for insect control, but it is certainly allowed.Thanks for your thoughts on the Academy. Obviously there will always be some people who think a product or service is too expensive, which is understandable. I’m getting lots of incredible feedback from members, so there must be something right going on there. As for what’s different about the Academy and this site – in the Academy you get 35-40 videos per month covering topics in great detail, while on this site I post 1 article or video every week or two.Hope you have a great gardening year!

  5. lawrosa1 on May 4, 2012 at 7:26 pm

    My previous comment was not posted I believe. Wonder why? Something about a moderator had to review it….LOL

    • Phil on May 5, 2012 at 4:42 pm

      Ya, it was automatically flagged because of the links, so I had to manually approve it.

  6. Ramana Peddu on December 24, 2012 at 4:00 pm

    Does sea minerals fertilizer have all the minerals that are in sea kelp fertilizer?

    • Phil on December 26, 2012 at 1:40 pm

      Yes, and probably more.

  7. Robert Pavlis on January 11, 2014 at 9:46 pm

    A lot of good info here, but the comment “plants prefer their nutrients in organic form, prepared by microbes” is incorrect. plants can’t tell the difference between nutrients from commercial fertilizer and an organic source because they are exactly the same. See http://www.gardenmyths.com for more details on this common myth.

    • Phil on January 13, 2014 at 5:05 pm

      Ya, I was rather loose on my word choice there – what I mean is that toxic fertilizers like urea formaldehyde and triple superphosphate and potassium chloride often damage the soil’s chemical and biological balance. When the chemistry gets imbalanced, nutrients get tied up and soil structure is damaged. When soil biology is killed, the plants don’t get the benefits from that biology – minerals, vitamins, water, defense against predators, soil building, etc.What I should have said is that plants are healthiest when they have a healthy soil food web to work with, so let’s not hinder these natural processes in favor of force feeding the plants directly with just 3 nutrients.

  8. Larry Riley on March 11, 2014 at 10:21 pm

    I just returned from a feed and seed mill . I have a few peach trees a few pecan trees,so I asked google how best to take care of them and was told by google to use a certain amount of nitrogen the first time and adding more as my trees grew older. Well I asked at the seed mill about this and they said no,no,no,use 10-10-10 for your fruit and nut trees! I’m also growing tomatoes and cucumbers and all the bag of 10 10 10 it has a picture of beautiful tomatoes. What is going on! Should I use 10 10 10 for my fruit trees and nut trees? Also for my vegetable garden. I am now more confused than ever HELP HELP! !!!!

    • Phil on March 12, 2014 at 12:55 pm

      Unfortunately, it’s a little more complicated than saying one fertilizer is better than another when it comes to fruit and nut trees. Ultimately, it depends on what is going on with your soil. Here’s my main fertilizer page where I discuss organic fertilizers in general: https://www.smilinggardener.com/sale/organic-fertilizers/

  9. CT Organic on October 15, 2014 at 10:53 am

    I add some ashes from my wood stove into my garden plot in the winter, coffee grinds in the spring an fall, along with home made compost, organic grass fed manure, worm castings, and I till in baby rye/wheat in September

  10. Doug on September 20, 2016 at 5:08 am

    Hi, I am working in my forest area where the forest floors have not been disturbed for over 25 years. I try to maintain a natural for the animals and birds. I have made a trail to the area where I am viewing area. I am trying to limit disruption (damage) the pristine environment. I was thinking of fertilizing the area I have compressed and broke down to help the area return it to its’ original condition. Some plants are sword ferns, firs, cedars, moss, rhodies, berries, birches, daffodils, small leafy bushes, etc. I live in the NW .Any education or advice would be greatly appreciated .Doug.

    • Phil on September 24, 2016 at 11:46 am

      I wouldn’t suggest any fertilizer – just leaves. It sounds like you’ve done minimal damage, so the forest will fix it over time.

      • Doug on September 24, 2016 at 6:04 pm

        Thank you for your time and advise.Doug

  11. only126db on September 29, 2016 at 7:08 pm

    I started my first container grow of hot peppers (just did final harvest) and used a 10-10-10 fertilizer and from what other growers expressed I did quite well. Now my problem is that it seems I can no longer get the fertilizer I had used. Time to try something different…..

  12. Erin Davila on April 8, 2017 at 5:06 pm

    What do you suggest for canna lilies then?

    • Phil on April 13, 2017 at 10:29 am

      Well it depends on the fertility of your soil, as every soil is different, but good compost will go a long way, and then monthly fertilizing with liquid fish fertilizer or sea minerals should have you covered.

  13. Garrett Jon Parker on April 23, 2017 at 4:05 pm

    This will be my first year doing a vegetable garden at our local community gardens. The plots are going to be fertilized with 10-10-10 fertilizer. What can I add to the soil to give the plot a better chance?
    Thank you for any advice…

  14. Mark Newton on May 13, 2017 at 9:07 pm

    I had a garden in the front yard that was doing ok, my wife didn’t like the looks of it for people driving up, so I moved it to the back the house not thinking it would do as well, to my surprise it produced twice what the other garden did, but after 3 years it didnt seem to produce as well, and seems to be lacking something. I tried 10/10/10 and it seemed to produce a lot of green plants but no abundant fruit. Beets had great leaves but small beets, tomatoes had 5 ‘ plants but fruit was small and not abundant, what is this garden missing? I have a lot of clay soil, have added sand , buried leaves from previous year, added manure from Walmart, added topsoil from Walmart, soil is not black but brown looking, Help

    • Phil on May 16, 2017 at 8:51 am

      Sand won’t generally help much, nor topsoil. Burying leaves can cause some problems in the short term, but should be helpful in the long term. Same with manure. But other than that, it’s hard for me to say what’s wrong. Sending a soil sample to a good organic lab and getting recommendations from them would give you some clues as to which nutrients are deficient/excessive.

  15. Rose Ann Sabas on August 11, 2017 at 8:04 am

    10-10-10 fertilizer is really an organic? 10-1010 fertilizer was made from what organic matter ?
    what are the organic contents and active ingredients ?

    thank you

    • Phil on August 19, 2017 at 8:46 am

      No, it’s not organic.

  16. Jack on August 12, 2017 at 6:32 pm

    Hello
    What is better for gardening. Composting in a composed bin or direct composting meaning that you add your vegetable scraps directly into the soil and Let it breakdown by the microorganisms?

    • Phil on August 19, 2017 at 8:50 am

      Good question. I don’t know that there’s a correct answer here, as there are advantages to each.

  17. Alan Reubel on September 8, 2017 at 5:44 pm

    What is the best fertilizer % for evergreens on Long Island NY….probably won’t do soli testing and ready to apply. Also, when to ppaly in Fall & Spring ?

    Many Alan thanks…..

    • Phil on September 22, 2017 at 3:52 pm

      Of course, it depends on your soil, but in general for evergreens I say don’t apply too much. Compost may be sufficient. If you don’t have compost, something broad spectrum like rock dust, alfalfa meal or fish meal could bring some benefit.

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