Overfertilized Plant

Last week, I overfertilized my garden. I realized about 24 hours after the fact. It just hit me and my heart started going for a little jog.

In my case, it was not the usual N-P-K chemical fertilizer that is often the culprit, but Borax, which I needed for the boron.

Of course, one doesn’t go applying boron willy-nilly, but I have had a deficiency in my soil. Watch the video below to see the results, and remember, organic fertilizers are not all benign.

Click for video transcription

This transcription will have some mistakes because it is partially automated.

Hey guys! It’s Phil from smiling.gardener.com, and I, as I, as I kinda of loaded to last week, I think in my written blog, I over fertilized my garden last week, and I want to show you what that looks like and give you a few tips.

I just realized that matters most show you the compost tea, I have brew in here which I will be applying tomorrow, supposed I should make a video about compost tea sometime, so here’s what happened and I realized that I over fertilized my garden about 24hours later or something I was just doing something out here, and I was like “ahhhh…” and what happened is I had you know I did everything right.

I had a soil test, and I followed their recommendations, you know most of their recommendations that I did a couple of things in my own that I thought made sense. And then about a week after that, there was one nutrient that I had not got around to applying and that was boron. Now boron is something that’s needed at like, yeah! It’s like one to two parts per million that boron is needed. So it’s a tiny tiny, it’s a trace mineral really, but very important.

Boron is needed for, it works a lot with calcium to help transport water and nutrients throughout the plants, it’s really important for fruiting and you know I’ve been reading a lot about boron in the last half year, because I wrote a book and I just learning about it, and got excited about it. And so what I found out that I had just little bit of a boron deficiency.

I thought cool I’ll bring in some boron, and it’s really useful, it’s really useful when you’re seeding to have enough boron and soil and stuff like that.

But what I did, was I over fertilized my garden, I did this about a week after I read the soil test, and just- in my head I had 20 pounds. And of course, on a soil test, it’s often gonna be per acre. Soil was 20 pounds per acre and I had in my head that it was 20 pounds per thousand square feet.

Which stupid coz I know that boron is just like this little trace nutrients, so I’m sitting here with a box of borox which is a common way to apply boron and I’m putting borox all over my garden, not thinking that you know of course, you only often using a teaspoon and tablespoon of this stuff.

So silly me, anyway, that’s okay so what else I do is I’ll show you which showing up on some of the plants is what I believe is, is a boron toxicity. It’s not that what I walk around knowing what boron toxicity looks like that’s not what I think about that often.

But I look it up, and you know if I didn’t know that I just applied what I end applying is about 30 times too much boron. If I had not known that I would not noticed born toxicity it could look like a lot of other things you know, that’s why it really hard to look at the plant.

Like some people claimed to do and know for sure that’s it’s just a for certain deficiency or toxicity, it’s little more complicated than that. But in this case, since I know I just applied 30 times too much boron, I’m thinking, it’s a born toxicity.

So let’s just have a look here. You know I have some, I don’t know what you’ll be able to see. I have some Thrives they’re starting to yellow a little bit on the ends. My oregano, starting to get some little brown spots, a parsley, it has a couple of leaves and it’s turning a little bit brown, my some my garlic is turning, and onions are tuning into yellow at the ends, not that one so much. But if we really walk over and look at the tomatoes, tomatoes are kinda of sensitive plants so you can see it really well in them.

Right down there, and it’s a especially the order leaves which makes sense and you know it’s not so much the younger, newer leaves appear, they seem not as affected a little bit on the tips. So I don’t know if you could see that, and the yeah! There’s a couple others too and you know some don’t seem to be affected as much.

You know we’ll see what happens, in this case, a lot of this here was a sheet mulch. I would not always plant in to anyway. So it’s not the end of the world to me, I have more garden over there that I didn’t apply many borax too, so I have lots of place/space to grow food.

But also, you know, boron is a minerals so it’s not just something that’s not gonna disappear if I leave it for a year, so we’ll see what happens, anyway, that’s overfertilization, so what I thought I do is give a few tips here, I guess it’s gonna be a little bit long video but just some tips if you happened to have overfertilized you garden.

You know the first one that you’ll hear often is water the area really well and I think for the most part that makes a lot of sense, so I certainly did that. You know, the ideas that you’re gonna water some of the- whatever you overfertilized with. I’m talking about boron today, but usually when people overfertilizes their garden, it’s gonna be a chemical N-P-K fertilizers or something like that or a weed and feed.

In that case, you know you just want to water it and hopefully some of that will leach out. Now, it could be that you just watering it down throughout the whole roots zone, but to me it makes sense to do that, so that’s number one.

Number two tips when you overfertilized your garden is, you know you can go on line and look for look for, look for (oh, my hands are getting tired) look for in gardening forums and things like that but just be wary of following those recommendations because often people just spoke of stuff that’s doesn’t make any sense to me.

You know, I was looking at for my boron thing and people were saying things that did not make a lot of sense. Now often times that what they do is to recommend you to apply a certain nutrient to counteract your nutrient and that maybe an okay idea but it’s not that simple, that you can just go and apply you know, soil is more complicated than that.

What I would do is I would contact your soil lab, you know, or if you have soil test results like I did, contact your soil lab and I didn’t do that and the reason I didn’t, is coz I’ve been bugging them a lot lately with a lot of questions that I felt kinda like a they’re getting sick of me.

That’s stupid, I shouldn’t done that, because this is the big issue, I have boron all over the place, and maybe they would have said something and maybe they would have told me to apply certain nutrient and that I would, I would trust you know, what I actually end up doing because I know boron and calcium work a lot together as I applied a little bit of calcitic lime and a little bit of liquid calcium.

Hoping that I would kinda tie up a little bit of the boron, maybe that’s wishful thinking. But I knew it’s a good time of year that would be applying that. Anyway, so just a little bit of that in that case, I was comfortable with that, but people on the forums were recommending you know, gypsum and other stuffs and you know, I just don’t know if you can always trust that unless you can collaborate a few different resources.

So that’s that tip, next tip when you overfertilized your garden is don’t go applying fertilizers unless you know you need them. Now in my case, I did I had a soil test result and I just did a stupid mathing. But I, you know, in this case, it was boron if it’s really not gonna be the end of the world, if I didn’t apply boron, you know, I was putting compost tea, and I was applying a broad spectrum things like sea minerals.

I probably, had enough boron with that and I was just getting a little too cute with trying to perfect the soil. You know, it’s not that simple that you just- I just think it’s better to used the precautionary principles and apply things more when you know you’ll need them.

Certainly as I said that before, you wanna have soil test which I did have soil test you wanna have some soil test as I talk about in the academy. You know I say don’t worry about these things like boron and I am breaking my own advise, but don’t worrying on those things until you’ve work on the main things which is calcium, phosphorus, you know, you’re not gonna do as much damage by applying some lime.

As long as you know which lime to apply based on a soil test, so do all of these based on a soil test. Definitely, don’t go applying N-P-K fertilizers, just for this, just for good measure. You know, coz you’ll probably don’t need those nutrients, it certainly not the proportions that they are in the fertilizers, like you know like 10 10 10 or something like that you know that’s –that’s not make sense to do that.

The other one is, you know, organic fertilizers can cause problems, too. Boron can be used in organic or cultured if you have a documented boron deficiency, so you kinda call it organic fertilizer. I’ve burned plants leaves before by applying too much fish, too much sea minerals, it’s possible to apply too much effective microornament, effective microorganisms and you could ferment, you can ferment the plants. It’s very, you know, this fermenting microbes, it’s just if you have young, tender leaves, you could apply too much if you don’t deluded enough. So this can happen with organic fertilizers.

You guys getting sick of tired, getting tired of looking at my face? I have a lot of tips here, the last one that I can think of is, you know when I- when I learned, I did learned how to do timberframing that in Costa Rica. One thing that I learned there is measure twice, cut once cause when you laid out this big log and you’ve really done a lot of time measuring it and it’s very easy to cut wrong and you’re in trouble.

So same with fertilizing, you know look at the label make sure you know how much to apply, it usually less than you think and look at your soil test, make sure you’ve figure out if it’s pounds per acre or pounds per thousand square feet and just take your time and do that.

So I’ve -I think that’s all of my tips I have for today for overfertilized garden. So, yeah! Just you know fertilized with caution, don’t go applying a bunch of stuff just for a good measure. If you do overfertilized, call a soil lab, a good soil lab, try to – you know maybe apply some water, water over the roots zone.

OH! Another Yes! I do have another tip, last tip is apply some, I think it would be a good idea to apply some humate. If you have humate acids because they tie up the toxins in the soil. I know they can tie up certain things, and I wonder if they would tie up with some of the boron.

Also, if you apply organic matter and some, some compost tea like I’m brewing here or some EM maybe some of those microbes would do something with the- those nutrients that you have in there that you have too much of, maybe they’ll get them to their bodies, maybe they’ll biologically transmit them into something else.

You know, we don’t really know, but if you can improve that soil food web, maybe they will help buffer those toxins and so will the humates, humate acids organic matter.

So that’s my last tip, so that’s I don’t know how long this video gonna be but hopefully you’ll still with me. If haven’t picked up those 15 Vital Organic Lessons for Becoming a Better Organic Gardener, you can get those at smilinggardener.com, right on the main page there.

And those are just a bunch of lessons that I think that are really cool, that I thought were really cool when I was studying organic gardening so for the first time. So hopefully this has been helpful for you today, I hope you’re enjoying your gardening season and I’ll see you next week.

I thought I would leave you with a few tips in case you ever find you’ve overfertilized your garden, too.

Overfertilized Garden Tips

  • If you’ve overfertilized, irrigate heavily. That’s the general advice and it makes sense to me that it would be a good idea to wash some of the fertilizer out of the root zone, although I suppose it could be possible that watering would just spread the excess throughout the root zone, right? But still, I watered like crazy.
  • Be careful of listening to advice you read on gardening forums. They often make additional fertilizer recommendations to counteract the fertilizer you applied. In some cases, the advice may be good, but in many cases it’s not. The soil is more complicated than just throwing on one thing to balance out another thing.
  • That being said, consult a good soil lab and they may some good advice about what to do, including adding a specific nutrient to tie up the toxic nutrient(s) in your overfertilized soil. I actually didn’t call the guys at my lab because I’ve been bothering them with too many questions lately, but I really should have. In this case, I don’t know what they would have said because boron is just a little trace mineral that doesn’t get as much attention as the others, but it would have been a good idea. Actually, I’ll email them right now and see what they say – should have done that in the first place. I’ll update this if they have something to add. Update: They said basically what I did: humates, microbes (compost tea/EM), fish/kelp, calcitic lime, calcium nitrate.
  • If possible, apply organic matter and/or a microbial inoculant such as compost tea or effective microorganisms (EM). Perhaps the microbes will do something with the excess, tying it up in their bodies or even biologically transmuting it into something else. Stranger things have happened. Also, if you have humates, they are good at tying up toxins, so they may help out.
  • When I learned how to timberframe, I learned the adage “measure twice, cut once”. The same goes for fertilizing. Double check the instructions on the label or on the soil test before you begin. It’s easy to overfertilize if you don’t know how much you should be applying. You’ll usually need less than you think.
  • Don’t fertilize with specific nutrients such as nitrogen, phosphorus, potassium, magnesium or whatever else unless you know you need it. That means getting a soil test done – not a home test kit and not the local soil lab, but a quality lab (I’ll talk about that another time). In this case, I had a test, but I just made a stupid-Philip mistake, and in my case, it was really not vital that I apply boron so I should have just left good enough alone.
  • Be careful with organic fertilizers, too. I’ve overfertilized plant leaves before with too much liquid fish and too much sea minerals. Too much EM can cause problems as well.

Any other overfertilization tips you would add in here? Any questions for me? Let me know below.


  1. Mdunn80 on June 11, 2011 at 12:32 pm

    I was wondering what you think about those of us who just add as much compost and manure and straw to our gardens each year? I’ve never gone the “fertilizer” route besides the three I mentioned above. Thanks!

    • Phil on June 11, 2011 at 2:38 pm

      Those 3 things go a very long way to improving your soil. Composting andmulching should generally be 2 of our main focuses, and you can often growfairly healthy gardens just by doing that.I get into using specific fertilizers (based on a soil test) in order totake the garden to the next level, growing even healthier food plants thancan usually be achieved with just organic matter – plants that will not beattacked by pests and that will be so nutritious that they can store formonths and can support optimal human health. Even then, most of thesefertilizers are not to be used indefinitely, but rather in the short term tobring the system to a balance.I get into much more detail about why fertilizers are important for this -and how to use them – in the book. Still, what you’re doing is the basis forgood soil management – improving the organic matter content of your soil andthe health and diversity of the soil food web. Hope that answers clarifies abit.

  2. Ben on June 16, 2011 at 5:48 pm

    Thank you for showing your humanity in the over fertilization video. I too have had the experience of over fertilizing in one of the forms you referred to, in which you mentioned having burned plants with too much fish and too much sea crop.I had that experience with sea crop, when the distributor suggested to me that it was okay to do a foliage spray with 1:100 solution. Well I burned a valuable plant that I was developing for a stock plant from which to take cuttings.The good thing is that when you add only one variable at a time, you have a better chance of figuring out what happened. The plant survived and I flushed it and sprayed with clean de chlorinated water and put it outside. All new growth is as it should be. So lesson learned, but like you, a little self reprimanding later, because I new I new better. Famous breeder D J Shorts who is renown for some of his connoisseur herbs, suggest use one half the manufactures recommendation to start, because the wost case is a small crop rather than a damaged plant. What a kind thought.Another sea crop discovery, although this is not strictly a one variable experiment, I have found that a 1:500 weekly foliar spray with sea crop reduces powdery mildew. I say not completely one variable, because I have also been thinning out plant pot density and keeping upping reciprocating fan air circulation to 24hs instead of just daylight hours. However, with that as a qualifier, I have seen no PM start up on younger plants and I have seen a dramatic retreat of PM on mature plants in the same area.

    • Phil on June 16, 2011 at 5:50 pm

      Thanks for sharing your experiences. I’ve read that Sea-Crop ( https://www.smilinggardener.com/sale/sea-minerals-fertilizer/ ) at a 1:200 ratio will help with powdery mildew. That’s interesting that a 1:500 ratioworks, too. I also read some research where 2ml per 1000 square feet of EM (probably mixed with something like 500 parts water) controlled powderymildew. It’s amazing that these small amounts can have such big benefits – shows that using more is definitely not always better.

  3. PatrickNorton on August 16, 2011 at 6:28 am

    Sometimes it is very helpful to consume supplements like iron,calcium etc.Liquid Calcium

  4. Charles on March 5, 2012 at 3:23 am

    After fertilizing too much you should water lots, but only if the soil is still draining. If you have a poorly drained site oxygenize you soil. Water is a special molecule and it attracts the extra n-p-k and other elements. As the water leaves your yard it moves them away/around. Pretty much all down to chemistry.

  5. Helena McDonald on July 20, 2017 at 5:06 pm

    I used “borax” to kill my ant problem, but it also killed the vegetation, how do I get the borax out of the soil? I can’t purge with water on a well.

    • Phil on July 25, 2017 at 12:53 pm

      Other than deep watering, I’d apply compost and perhaps other microbial inoculants and it will gradually be taken care of.

  6. Delmar Connick on July 1, 2020 at 9:56 pm

    I fertilized my garden with potato fertilizer and nothing much grew.Will watering it help or am I doomed for this year?

    • Phil on July 3, 2020 at 12:39 pm

      Impossible for me to know what the issue is. Water is important but it’s unlikely that it’s the only solution.

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