newbie 511 mixer problems/ bark and nitrogen?

nycgarden(6)June 2, 2012

I'm trying out the 511 mix for the first time this year and am having some problems. As you can see from the pictures below, I planted cucumber and eggplant at the same time in the 511 mix and a commercial potting mix.

The non 511 mix plants are doing much better than the 511 mix plants. These pictures are taken after about 2 weeks in the ground. I use the recommended Foilage Pro 1x a week full dose fertilizer regiment though I skipped the first week.

I also have bean plants that are in the 511 mix that are very healthy. Which leads me to my next question. Some farmers at the farmers market mentioned that bark naturally repels nutrients especially nitrogen? Anyone else hear of this? The yellow leaves on my eggplant seem to indicate nitrogen deficiency. Should I fertilize with FP every watering?

Any other recommendation would be greatly appreciated,


Thank you for reporting this comment. Undo
Ohiofem(6a Ohio)

Bark does not repel nutrients. When sap wood decomposes it does use a little nitrogen in the process. But pine bark does not do this to a significant extent. And if it is partly composted as called for in 5-1-1, it does this even less. I am wondering how much and what kind of lime you added to your 5-1-1? I've never experienced the kind of problem you have and I'm on my second year of growing many vegetables in it. Your pictures do suggest some kind of imbalance.

    Bookmark   June 2, 2012 at 7:22PM
Thank you for reporting this comment. Undo
redshirtcat(6a MO StL)

There are a number of issues with pine bark that need to be dealt with. You should check out these 2 articles to start:

One of them is specific to blueberries but the pine bark information is still useful outside of blueberries.

Pine bark will decompose and in the process will lock out some nutrients as the microbes use them in the process of decomposition. The process takes longer for pine bark but it still takes place. The nutrient lockout in pine bark should be more stable than in something like leaves or sawdust which will decompose rapidly (causing rapid decline in available N until the material is fully decomposed and the microbes die releasing the N back into the soil). The lockout is always temporary until the carbon source for the microbes is depleted (or reduced to the point that a certain portion of them die off).

You said something interesting at the end there. Your bean plants are doing fine in the 5-1-1, yes? If so then I would suspect N lockout (or deficiency) in the other plants. Bean seeds are almost always inoculated these days with beneficial bacteria which is capable of N2 fixing (they take nitrogen gas from the air and convert it into plant-usable nitrogen). Even if your seeds weren't inoculated it is likely that bacteria made its way into the pot and has nodulated the roots of the bean plants.

What I'm saying is that the beans are likely getting more nitrogen than your other plants and if they look find and the others do not then I'd start by adding N to the other plants. Maybe your pine fines weren't aged enough or maybe the pine bark contained some sapwood that is causing N lockout or maybe you just aren't fertilizing enough in general...

    Bookmark   June 2, 2012 at 11:19PM
Thank you for reporting this comment. Undo
redshirtcat(6a MO StL)

Uhh. So I didn't look closely at your pine bark before writing my reply.

It is almost certainly N lockout that you are seeing. The pine bark you're using doesn't appear to be broken down at all. It looks like very large particles of fresh, uncomposted pine bark. I can even make out sapwood in one of the photographs.

I made a basic video awhile back that showed what pine fines should look like and how to make the 5-1-1: Al's 5-1-1 mix how-to video you might want to check it out... even though I repeat myself and should re-do it for clarity and etc.. you can at least see what it should look like.

Or you could try for Fafard's mixes which are also good. I use their "nursery mix" or mix #51 (custom high-bark mix). Either will work well and would be comparable to 5-1-1.

    Bookmark   June 2, 2012 at 11:25PM
Thank you for reporting this comment. Undo

Thanks Everyone,

Redshirtcat, do you think I can salvage what I have by watering with Nitrogen fertilizer like seaweed extract to up the N?

Or are my plants gonners?


    Bookmark   June 3, 2012 at 8:11AM
Thank you for reporting this comment. Undo
greenman28 NorCal 7b/8a

I use uncomposted bark exclusively, and I don't have these issues, either.

I wonder if the mix is staying too wet, and making it difficult for nitrogen
and calcium absorbtion, or something like that?


    Bookmark   June 3, 2012 at 11:55AM
Thank you for reporting this comment. Undo
Ohiofem(6a Ohio)

I agree with Josh. My pine bark fines are uncomposted as well. I do add Osmocote controlled release fertilizer at the rate of 1 tablespoon per gallon of mix. Here's a photo of my eggplants 12 days after putting them into 5-1-1 outside.

Something else is going in with your plants.

    Bookmark   June 3, 2012 at 2:35PM
Thank you for reporting this comment. Undo
redshirtcat(6a MO StL)

Not sure what else to say. I disagree. In the one photograph I count 9 pieces of sapwood on the top layer. I assume there is more below. No matter what you think about the bark the sapwood is locking out N for sure. The bark also appears too large and too uncomposted to my eye as well.

My theory also accounts for the success of the bean plants.

I also note the very light green color in the first photograph. I think your plants are lacking for N. I suppose it's possible they are lacking for N because they are waterlogged as Josh suggests but it doesn't seem likely given the size of your bark.

And no, I don't think seaweed extract is going to cut it for extra N. Were they my plants (and I have 3x eggplants and 4x cucumbers in 5-1-1 in pots this year and another 3 cucumbers and 2 eggplants in earthtainers) - I would move to adding fertilizer with every watering at reduced rates (1/4 tsp per gallon at every watering). If the total fertilizer would be less than the 1 TBSP you're giving them now (if it's cool where you are and you water less than 4 times a week) then up that to 1/2 tsp at every watering (for the plants in the 5-1-1).

It doesn't help matters that you left the soil completely lacking in fertilizer for the first week. I was just reading last night in the 3rd edition of Marschner's 3rd edition that nitrogen reserves in most plants will be depleted after 12-48 hours. There was likely 0 available nitrogen in your soil for that first week. Not surprising that the plants are suffering.

I assume you added no starter charge? When you build the 5-1-1 you should always add a starter charge of fertilizer. CRF or something, anything. The combination of sapwood + no starter charge + no fertilizer for a week. I'm convinced it's missing N.

    Bookmark   June 3, 2012 at 2:59PM
Thank you for reporting this comment. Undo
redshirtcat(6a MO StL)

Sigh, I wrote tbsp when I meant "tsp."

I hope you take my meaning. I hate that we can't edit posts.

    Bookmark   June 3, 2012 at 3:03PM
Thank you for reporting this comment. Undo
Ohiofem(6a Ohio)

I do agree it's probably missing N, and I do agree that it's a good idea to include CRF in your mix and/or fertilize immediately. I also agree with redcatshirt's advice to start fertilizing at a higher rate immediately. Your plants should show significant improvement within a week. But I am still concerned that there could be a problem with the pH of the mix. If your water is hard or you think you might have added too much lime, you might want to add a tablespoon of vinegar to each gallon of water you use to water them with.

    Bookmark   June 3, 2012 at 4:55PM
Thank you for reporting this comment. Undo

Thanks everyone,
I'll be adding a 1/2 dose of FP with each watering to see if that makes a difference. I'll also add some CRF Osmacote Plus as suggested in redshirtcat's video.

I'll also test the ph of the soil by taking some samples and soaking them in rain water and testing the result

It has been quite cool and rainy here the last few weeks. I find my 511 mix stays moist below the first couple of inches for over a week without watering. Is this normal?

    Bookmark   June 4, 2012 at 8:55AM
Thank you for reporting this comment. Undo

I've experienced the same problems with uncomposted bark fines.

Nitrogen lockup does seem to be an issue.

Another important issue is that uncomposted bark fines don't seem to be able to hold the nitrogen well, so that after a watering or 2 with just water, all the nitrogen is washed away.

Yes use CRFs, and use liquid foliage pro.
I've been amazed at how much foliage pro is required to get the leaves green again, once they display yellowing.

Regardless of any recommendations on fertilizer strength, you should fertilize with every watering and keep increasing the dose until the leaves turn green again.

I'd pick a dose, water, wait 3 days to see how the plant responds. If you don't see it greening, then increase the dose and repeat. Also make sure in the 3 days of seeing, that it is warm, the plant will only green up fast if it is warm outside.

    Bookmark   June 4, 2012 at 3:35PM
Thank you for reporting this comment. Undo

Yeah, I've had the same problems with the 5-1-1. N deficiency if I only use 1/4 tsp of FP every watering. Now I use 4ml of FP per gallon, which is about 4/5ths of a tsp.

    Bookmark   June 4, 2012 at 4:15PM
Thank you for reporting this comment. Undo

Agree with posters about composted bark fines. First thing I noticed was the red color of the bark. The stuff I buy is almost black. It likely contributes N, whereas the uncomposted bark likely aborbs it. Adding CRF may help overcome some of the issues.

    Bookmark   June 4, 2012 at 4:16PM
Thank you for reporting this comment. Undo

I'm also a new user of 5:1:1. My bark looks very similar to yours. I'm not far from nyc, maybe we have the same source. You did say you added lime, right? In my case, I made up 5:1:1 with half the recommended amount of lime.

A few weeks after transplanting my tomatillos into the mix, I noticed some yellowing of the older leaves. Some reading led to to suspect Mg deficiency. I believe that while FP does contain Mg, the concentration is a little on the light side. So I sprayed the foliage and also watered them with Epsom salts, and within a few days the problem seemed to go away. It could just be coincidence, but otherwise my fertilizing regimen did not change. Don't know whether this might help in your case, just my two cents.

Good luck.

    Bookmark   June 4, 2012 at 5:35PM
Thank you for reporting this comment. Undo
greenman28 NorCal 7b/8a

Maple Grove, was there a reason that you halved the Lime?

Lime provides both Calcium and Magnesium, so I could certainly see a low Magnesium count.


    Bookmark   June 4, 2012 at 8:53PM
Thank you for reporting this comment. Undo
redshirtcat(6a MO StL)

Also just as a general note about FP:

The typical suggested range of ppm N for crops is between 100-300 depending on what you are growing and sunlight conditions, etc. For "production" crops (this means anything that you're trying to get to grow as opposed to maintain at current size) the usual suggestion is between 150-200 ppm N for continuous feeding setups.

By my calculations FP will give you ~42 ppm N if you feed at the 1/4 tsp rate. This is far from adequate for most vegetables.

1 tsp FP should be something like 167 ppm N which is closer to where you want to be. If you're watering by hand you can look around for suggested ppm N concentrations for each crop and tailor your use of FP as necessary.

Really I would say that if you're just using FP on vegetables (no CRF in the soil or starter charge) then you're underfeeding even without taking into account N lockout which I'm pretty sure you are also suffering based on the quality of your bark.

    Bookmark   June 4, 2012 at 11:53PM
Thank you for reporting this comment. Undo


The bark you are having trouble with looks exactly like the bark I've used and had trouble with.

I always thought it was redwood, as I live in CA bay area.
Even after 2 years this red bark doesn't break down all that much.

Do you know what it is?

    Bookmark   June 5, 2012 at 3:03AM
Thank you for reporting this comment. Undo


No, there was no reason I halved the lime. Miscalculation really, for my first attempt at building a 511 mix. I used 5 gallons:1 gallon: 1 gallon and incorporated 1/4 cup each of dolomitic lime and Osmacote CRF. I think I was confused that the particular recipe I was looking at called for 4 Tbsp. of one and 1/4 cup of the other, when 4 Tbsp. = 1/4 cup. I intentionally cut the CRF in half since I planned to use regular FP applications, but then I botched the lime.

I can say that the growth surge following Epsom salt treatment was quite spectacular, although it could just be coincidence. I got a gallon of "Cal Mag Pro" which I will use in future to supplement my tomatillos and peppers to correct for the deficiency.

Incidentally, my bark looks very similar to OP as far as I can tell, and it was described as pine bark.


    Bookmark   June 5, 2012 at 9:17AM
Thank you for reporting this comment. Undo

I did add the recommended dose of lime to the mix, but will be testing the ph with a home kit (those capsules with the plastic boxes with color charts on them). Being new to this, I want to rule out all possible mistakes on my end.

It was listed as Pine Bark and was bought from Agway, which is a reputable outlet for agricultural supplies on the East Coast. Not too easy to find any source of pine bark in the city, so I'm limited in terms of selection. I had to special order this batch. I started with a full dose of FP yesterday and will continue every 3rd day until I see improvement, as per your suggestion. The CRF I will add when it come in on Thurs.

I did notice there is quite a bit of sapwood in the mix; as much as 5%. I tried to get most of the big pieces out, but it would take weeks for me to get every little piece out; kind of making it unusable.

Do you add anything else to your mix other than CRF? You mentioned a booster?

    Bookmark   June 5, 2012 at 10:18AM
Thank you for reporting this comment. Undo

Just to follow up, I did start a every 3 day regiment of FP and did see an improvement in leaf color.

I took samples of the bark mix from one pot in 3 different places, mixed it with some water in a mason jar, let it set for 15 min, and then took PH and N samples from one of those home kits.

My PH was off the scale; 7.5 + and N was either not registering or deficient.

Any advice for fixing this issue? I have plants that are growing, not very robustly, but still growing in this mix.

What should I do better next time so I can avoid this problem?

Thanks in advance for any advice,

    Bookmark   June 17, 2012 at 7:07PM
Thank you for reporting this comment. Undo
redshirtcat(6a MO StL)

My advice is to stay the course. Keep providing increased levels of N. For rapidly growing vegetables I would suggest no less than 1 tsp per gallon (FP) at every watering. With cucumbers you probably don't want to go much higher than that but you can check around online for ppm N for continuous feed and cucumbers and decide for yourself. The eggplant could probably use more.

In the future my advice would be to use bark that is more appropriate and to make sure you add a starter charge. Josh and I disagree on this. In my view you want partially composted pine fines which look nothing like what you have in your pots. If you want to know what I mean you can see my (annoyingly repetitive, I know) video concerning 5-1-1 preparation here:

I've seen Josh's and I think the bark he's using would be a problem in my growing conditions. I prefer my bark the way you see it in my video. There's a particular shot where I zoom in that is the best one to see the quality of the bark - the wide angle shot makes it look finer than it is but you will get the idea.

You can also get the idea of what it should look like by tracking down a single bag of Fafard #51 or #52 mixes. It's a pine bark based potting mix used by nursery professionals and you will see that the bark in that mix looks just like the bark I show you in the video above. The stuff you have there would be more appropriate for the gritty mix in my view.

Also note that if you use CRF as a starter charge and then let the soil sit around in damp and warm conditions for a long period of time you will kill whatever you try to plant in that soil down the road. If you use crf as your starter you want to plant in it immediately or make sure you keep it cool and dry.

Whatever you do in the future you do not want to put a plant into a soilless mix with absolutely zero nitrogen and then skip 1 week of fertilizing. That's asking for trouble.

Was the water that you used in the mason jar distilled? If not then all you did was read the pH of your tap water and you should redo the test with distilled (spring water and etc will not cut it). If you did use distilled then that's not a great number but FP will drop the pH over time if you keep using it (assuming your water quality is decent in terms of alkalinity).

Testing for soil nitrogen is not a simple process and I wouldn't trust any home kit to give you anything close to a useful number. Even if you send a sample to a lab it won't tell you all that much. N is more mobile than other nutrients in soil and rain/leeching and a whole host of other factors can cause soil readings to be difficult to interpret.

    Bookmark   June 18, 2012 at 1:40AM
Thank you for reporting this comment. Undo

Thanks redshirtcat,
I used tap water for the ph test but I've used the same method in the past and verified with a friend who sent the same soil sample to a lab, that the home ph test kit with tap water was relatively accurate.

I will continue to use FP with every watering, but should I try to correct the ph with soil acidifier? I have some from Epsoma that I could use. Just wondering if its best to not try to jerk the ph around while there is a plant in the container.

Also, is it your experience that the 511 stays moist for much longer than conventional potting mixes? Mine is dry on top, but a few inches down it can stay moist for over a week with out watering. Not sure if this points to another problem.

Thanks again for your advice,

    Bookmark   June 18, 2012 at 8:02AM
Thank you for reporting this comment. Undo

Tap water is not a good medium for a soil test. Even rainwater is better then tapwater when testing pH as minerals in your tapwater will buffer the pH. Rainwater is also good for watering, and the combination of rainwater and fertilizer may be enough to bring down your pH over time. Doing things gradually, is usually the best course.

As far as the nitrogen issue, I find that bark I buy comes in different stages of decomposition. I find that CRFs usually compensate for uncomposted bark or sapwood in the mix.

    Bookmark   June 18, 2012 at 11:45AM
Thank you for reporting this comment. Undo
redshirtcat(6a MO StL)

That depends on what you mean when you say conventional potting mixes. Properly made the 5-1-1 should hold far less water than any peat-based mix like miracle gro or etc. I don't think yours is properly made as discussed above but even if it were you might find the 5-1-1 appearing to hold more moisture if the plants you have in it are 1/3 the size of the plants in the other mix because they lack for N or what have you. Just to give you an idea the bush cucumbers I have in ~2 gallon pots in the 5-1-1 need watering twice daily here (they are ~5 feet tall currently and holding 3-6 cucumbers at any given time). My pots are undersized for cucumbers but the mix certainly drains quickly as well.

I strongly encourage you to re-test the pH with distilled water. I'm not sure if you are actually in NYC or not but I just checked your water quality report there and the pH of your tap water varied in the last report I see from 6.7-9.8 - your CaCO3 equiv looks pretty good but the pH could be anything. Just because your friend lucked out using tap water once doesn't mean that's a valid way to test (maybe his soil was closer to the tap water pH, maybe the pH of the water that day was closer to the soil, etc). You will also find the home test kits unreliable if you compare them to any decent pH probe. I've used this one successfully for several years now:

If you're really worried about the pH I would invest in a probe (there are higher quality more expensive probes than the one I chose - a replaceable glass electrode would be an additional feature you could look for). Then I would follow the pour-through method to test the pH of the leechate (and avoid testing the soil itself unless you're willing to disturb the roots of the plants and to take multiple samples and average them). That would entail watering as normal and then ~1 hour later pouring a set quantity of distilled water into the pot, collecting it as it leeches out, and measuring the pH of that water. You can read about it here:

I really wouldn't start doing anything to change the acidity short of using FP (which at a CaCO3 of 15-23 like the NYC report says you have will produce slightly acidic conditions in the pot over time) until you are quite sure the pH is high. Even at 7.5 you will still have most nutrients very available. If you start seeing signs of deficiency of Iron, Mn, Zn, Cu, or B then you could maybe take some drastic action. I don't see those in your photographs. All I see is missing N.

    Bookmark   June 18, 2012 at 11:48AM
Thank you for reporting this comment. Undo


Overwatering as redshirtcat indicates probably is not an issue. With a fast draining mix, especially in warm weather it is almost impossible to overwater.

Just the opposite, plant wilting b/c it cannot wick water fast enough, might be or become an issue as the plant gets bigger.

You should monitor any plant wilting during the day.

In one of my 18 gallon tubs, I have 3 ~1' tall peppers in a similar mix as yours. Even though I water the tub at 10 am, when the sunlight first hits it, by 11:30 on a 80 degree day, the plants start to wilt. Whereas I have peppers in heavier compost type mixes and they do not wilt (or wilt much less).
There is enough water in the mix, but there isn't enough feeder root hair contact with the mix to wick up the water fast enough, so the plant wilts. In the compost mixes the feeder roots are surrounded by mix and there is more "wickable contact" with the mix, so wilting is less.
In order for a plant not to wilt, it needs to be able to wick enough water and get enough oxygen at the same time. These two conflicting tradeoffs make it hard to optimize a mix for any given situation. No one mix will be best for different situations.

An ideal situation is the porous mix, but with regular watering several times a day (basically hydroponic flood and drain or continuous drip). But if you aren't home during the sunny, hot part of the day, then a porous mix won't work well in a hot, sunny climate.

I have to water my pepper tub at 11:30 to noon every day or they won't grow much. Since the sun only hits them at 10am and they wilt at 11:30, they would only get 1.5 hours of direct sun photosynthesis a day, hardly enough to grow a plant well. But when I do water them, in half an hour they total recover in the full sun and are happy for another 1.5 to 2 hours after that. So I would need to water them yet again at 2pm, when they do start wilting yet again. Sometimes I'll do this, but they become shaded again at 2:30 to 3pm so it really isn't that useful.

Bottom line, monitor plant wilt. If in a porous mix, right as or right before wilt occurs on a normal day, water it, just a little with diluted fertilizer solution. This covers the feeder root hairs with water and allows them to wick up enough water for a few hours.

By just monitoring plant wilt and leaf color, you can adjust whatever your doing daily and the plant should do well. You probably don't need to worry all that much about pH. And with Foliage Pro, you probably don't need to worry about nutrient specifics.

    Bookmark   June 18, 2012 at 2:21PM
Thank you for reporting this comment. Undo

NYCgarden, I started using 5/1/1 last year and made a lot of mistakes in the beginning.

The biggest mistake I made was not screening the bark. Did you screen the bark using a 1/2 inch chicken wire? There shouldn't be any pieces bigger than 1/2 inch. I save the larger pieces for mulch.

    Bookmark   June 18, 2012 at 11:33PM
Thank you for reporting this comment. Undo

Thanks first for all your help. I think the biggest mistakes I made was not adding a crf to start and using an incorrect amount of lime which created non ideal ph.

I did screen my bark through 1/2" hardware cloth and used the rest for mulch.

So far, the FP watering seems to be keeping the plants healthy. They're just not as robust as those in the commercial mixes.

I'll chalk this season up to a learning experience and try to be more careful next season.

Do any of you reuse your bark for more than one season?

    Bookmark   June 19, 2012 at 7:19AM
Thank you for reporting this comment. Undo

Do any of you use a mulch ontop of the 511 mix; black plastic or something like that?

    Bookmark   June 30, 2012 at 7:45AM
Sign Up to comment
More Discussions
Container Garden Vacation Watering
I'll be leaving for my wedding at the end of June and...
"tapla" root pruning question
Hi Al, I bought another Brush Cherry, and wanted your...
glowing pots
Not sure if this is the right place for this but I...
Miniature rose plant..
Got this from nursery yesterday .. But something is...
#15 pots for tomatoes.
I have accumulated 5 #15 pots for next years tomato...
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™