Misting the soil surface

[mad librettist]

So I just started doing this 2 weeks ago. Whenever I open up the cab, I mist the surface of my soil, even if I am watering. Always a mist.

Since adopting this practice, I have noticed an increase in life around the soil surface. I used to not be sure if wigglers were still in the pot, but now I can just scratch the surface to find one. I also now get more volunteer sprouts from the worm bin.

The obvious question is what about fungus gnats. But I figure if they show up and get out of control, then I will modify my practice.

If you top dress anything at all, have you considered, or do you already mist the surface of your soil often? Seems to me that keeping some moisture up there encourages things to actually live up there.

 

[DARC MIND]

i dont just mist my soil but i do foliar like once or twice every 2 weeks..misting both my media and leaves pretty well..
i find that a news paper on top of my soil, along with some compost and or coco coir keeps my soil alive about an inch down. i prefer to let my soil surface dry out some because of gnats, i use my own compost, ewc and soil that usually sits outside and its pretty common that gnat come with the goods.
the dry surface soil helps my gnats look for moisture in my soap or neem/water bucket and they drown..
this what works for me

 

[secondtry]

Hey,

Keeping the top of the media above 50% moisture content (by wet weight) is a very good idea; and actually keeping all the media above 50% moisture content is ideal (I term 50% moisture content "MCmin"). Staying above MCmin is required for the most healthy and effective soil food web and root respirations, etc; which leads to peak rate of photosynthesis (Pn), nutrient cycling, disease resistance, etc. However, most media has a "container capacity" (CC; the same thing as field capacity for soil but CC is for soilless media) of greater than 65% moisture content (which is not good), however, the point being that CC is a good deal higher than MCmin. The flux of moisture content from CC to MCmin is important for the amount of N-cycling in media from protozoa; they feed more after rewetting of media once the media reached MCmin. There are large increases (by %) of N after rewetting , thus the flux from CC to MCmin offers more N than keeping media at the ideal moisture content (e.g., 55-60%) all the time.


References:

Kuikman, et at., 1989

Effect of Soil Moisture Regime on Predation by Protozoa of Bacterial Biomass and the Release of Bacterial Nitrogen. Agriculture, Ecosystems and Environment, 27 (1989) 271-279​

Kuikman, et at., 1990

N-Nitrogen Mineralization from Bacteria by Protozoan Grazing at Different Soil Moisture Regimes. Soil Biol. Biochem. Vol. 23. No. 2, pp. 193-200.​

HTH

 

[secondtry]

Another point:

In peat and coir based mixes up to and greater than 30% of the water absorbed by that media is lost to "evapotranspiration" into the air (IIRC from Agro, et al., circa 2007). I mention this due to darkminds mention of putting newspaper over the media, in labs workers use saran wrap to reduce evapotranspiration but the problem with doing this is it encourages algae and hinders respiration of soil food web and roots.

Another point is coir and peat both hold a good % of absorbed water as "available water" which is water plants can easily use and the water lost to evapotranspiration is generally available water, thus leaving a greater % of "buffer water" (plants can use but not easily) and "unavailable water" (plants, bacteria, microfauna and mesofauna can't use) to comprise the water held in the media than without such intense evapotranspiration.

Both of those points are yet more reasons why aged pine bark fines are the ideal base for a soilless mix...

HTH

 

[DARC MIND]

i dont think the saran wrap works the same way as news paper, my news paper fully dries in about one day max after a soil drench and the media/mulch (compost/coir) under it also dries with in days. (pretty sure ther is no to very minimal hindering of soil respiration)
i also believe the percent absorbed or lost by peat or coir mixes can vary from percent used in mix (as you stated but), other amendments and percent used (compost, clay, humus etc),container used(some use smart pots, tubs, etc) and the grade of product. not all peat is the same and that goes for coir too.
lots of coir is either and or mixed of pith, croutons, long or short fibered, chips ect. for example in my experience 100% pith just stays too soggy and can hinder root development deep in the container
i think this boils down to everyones grow being a little different, we all dont use the same products etc etc and that plays a big role on how your soil/plants responds.
best way to know what works best is experimenting your self

 

[secondtry]

Hey DM,

Sorry about that, I didn't mean to imply newspaper works the same as saran wrap, just thought it tied together well.

Once media drops below about 45-50% MC the respiration of the soil food web suffers and respiration is (according to most scientists I have read) the best way to quantitate stimlui effects upon soil food web; plate counts are also a good method but less ideal AFAIU; it seems ideally one would use plate counting method (as Dr. Ingham, MM, CTGuys, etc use) and soil food web respiration.

All peat and coir based mixes loose a good deal of water to evapotranspiration like I wrote, I have plenty of references on this topic, adding other amendments helps mitigate it but it's still a concern as too much is lost, IMO anyway. Long fibre peat with greater "air porosity" (AP) than peat we most often use would loose less water to evapotranspiration your correct, but 99% of growers who use soilless media as coir and peat based mixes loose a lot of water to evapotranspiration and have much less air porosity. In fact, AP lower than 15% will hinder plant growth (according to Cornell, U.), and lower than 12% will prevent plant growth while other studies found less than 10% AP will prevent plant growth; NCSU found all tested peat and coir based mixes have AP below 15%; most often below 12%!. One may suggest those figures are incorrect because peat based mixed grow plants well, and I agree peat does, but one must consdier teh AP below 15% is at CC, when soil moisture is below CC the AP will increase as "water-filled porosity" (WFP) decreases.

All tested coir and peat mixes have too high CC (> 65% MC), including peat-lite mix, professions mixes, commercial mixes, etc. These data come from NCSU labs using their porometer testing over 2,000 different soilless mixes. There are many issue which effect the CC of peat and coir, too many for me to list here, but suffice it to say, any soilless mix you/I/etc are using has high much CC...that also goes for grower who use soil.

The factors that effect how plants grow and soil food web are the same for all media, there are ideals of media physics which both plants and soil food web functions best within, it matters not what media is being used.

All these biological responses are very well studied already, and the studies offer much more usable quantitiations than we could by simply growing and looking at plants and microbial plate counts, that doesn't give you enough info at all. There are known and proven benchmarks which allows for the highest Pn (for plants like cannabis), and highest root and soil food web respiration, N-cycling, mineralization, etc, etc. What we need to do when developing a media is to try and reach these benchmarks and test the media with a porometer and tensiometer.

In fact, this is what I have been doing non-stop for weeks, and off-and-on for over two years: trying to understand relevant aspects of soil chemistry, physics and microbiology and then combine them into ideals for soilless media (it's way more complicated than it sounds)

Once I have a porometer and tensiometer I plan to carry out a lot of testing with my media and medias often used by cannabis growers (e.g., pro-mix bx, sunshine mix #4, LC mix, coir mixes, etc), in fact, I would like people to send me samples of their custom mixes so I can tests and catalog it and compare it to other media in the catalog. Then I will report the findings and all you gals/guys can use the data to buy the most ideal media you have available, or make your own.

The three issues which complicate matters are container height (effects physical properties), packing method (copy NCSU method), and watering method (slow drench post packing). I will test the water tension (via. tensiometer) in 30 cm and 45 cm tall containers, not shorter as I don't' think it's wise to grow cannabis in shorter containers.

I am writing two papers: one for academia and one for folks like us, the latter will be much less technical and be a "just the facts" type of paper.

Please see this thread for more info on soilless mix properties, etc:

"Development and Harvest Yields of Greenhouse Tomatoes in Six Organic Growing Systems"
https://www.icmag.com/ic/showthread.php?t=158911


HTH

 

[secondtry]

Ps.

One can measure media respiration fairly easily at home. I have a great paper all about it, I also have a paper which tells one how to separate respiration of roots and soil food web from gasses of decomposition but it's heavy math and I have to re-read it a couple of more times to understand it...if anyone wants to read it and explain it to me/us I'd be very grateful! I'm not looking forward to digesting it on my own but I will if I have to. THanks!

 

[MrFista]

How heavy is the math? I 'might' be able to help decipher some of it. I'm only now getting a handle on exponential and decay functions, derivatives, waves etc. No physics till next year when the math is tight...

On covering media - re newspaper, saran wrap... What about breathable cloth, like cheesecloth? Thoughts?

 

[Microbeman]

landscape cloth

 

[secondtry]

Hey Mr.F.,

Mr Fista:
How heavy is the math? I 'might' be able to help decipher some of it. I'm only now getting a handle on exponential and decay functions, derivatives, waves etc. No physics till next year when the math is tight...

On covering media - re newspaper, saran wrap... What about breathable cloth, like cheesecloth? Thoughts?

Great, thanks for the offer, the math shouldn't be too heavy from what you know. I will attach the paper to this post, I also attached the PFD (I made from a webpage) telling one how to find soil/media respiration. Let me find them real fast...

I like DM's method of newspaper to keep top of soil moist, in Nature that would be taken care of by competitor and/or companion plants, or grasses, rocks, clouds, etc. I do like your suggestion of cheesecloth though for five reasons: 1) it's white so it reflects, less heat is held; 2) it can be moistened and hold moisture maybe better than newspaper; 3) it's breathable (like you wrote); 4) I can drench water right over/thru it, no need to remove it, and 5) it's cheap. I really like that suggestion, thanks, I will try it for sure! Thanks to you, DM and of course MadL for the thread

Let me know if you need more info, or papers or help defining terms, concepts, etc.

 

[secondtry]

landscape cloth

Hmmm, good idea, does it allow water to pass easily? (edit: I think there are different 'grades' correct?)

 

[secondtry]

In outdoor containers I used to add an inch or two of bark (not mulch, bigger bark pieces to allow water to pass easily) to top of soilless mix with peat, this helps a lot. I don't know why I didn't think of applying that to indoors, esp. considering I'm such a aged pine bark fines proponent, ha.

 

[secondtry]

@ Mr.F.,

Here ya go:

I misinformed you before, the model separates soil respiration into the Co2 gasses from the soil food web (visa-vie organic matter decomposition/mineralization as Co2 production) and that from roots and rhizosphere ; after another quick look the math isn't hard, just complex. The model was based upon yearly figures and I didn't really look at the equations so I don't know how they are setup.

One quick thought I just had, considering I haven't looked into this very far (or at all really) so my thought might be silly, however, you may need to know the OM fraction of the media being tested. The reason I write this is the model used to separate soil respiration is based upon SOM (Soil Organic Matter) data from Canadian crop soils; our soilless media could be higher in OM (note: ideally OM for soilless media is at least 5-10% vo/vol and Luebke Humus Score should be ideally at or greater than 15-30). If that is the case and you do need to find % OM I also attached a PDF which tells one how to easily calculate % OM at home (by finding ash IIRC, which can also tell one % volatile solids, but I digress...)


You will need (at least):

• equipment for soda-lime test (not expensive, listed on that webpage)
• soil thermometer, I suggest using a long compost thermometer, they are accurate for the most part and long
• pH pen (for PourThru method to find pH of media, or use the more accurate method to find pHw of media; I can describe it for you but you still need a pH pen)

Step 1

Measure soil respiration (Co2):

"Decomposition and Soil CO2 Emission"
Detailed Description of the Experiment (written for students)
http://tiee.ecoed.net/vol/v6/experiment/soil_respiration/description.html

One of the most common methods for measuring soil respiration, the soda-lime method, is remarkably easy and does not require expensive equipment. As a result scientists all over the world have employed it (Grogan 1998). Soda lime is a variable mixture of sodium hydroxide (NaOH) and calcium hydroxide (Ca (OH)2) in granular form. It’s commonly used in laboratories as a desiccant because it readily absorbs water vapor from the air. Because of its alkaline properties soda lime also removes carbon dioxide very efficiently from the atmosphere according to these reactions:

2NaOH (s) + CO2 (g) « Na2CO3 (s) + H2O (ads) [1]
Ca(OH)2 (s) + CO2 (g) « CaCO 3 (s) + H2O (ads) [2]​

Step 2

Find soil organic matter (OM) and soil moisture content (by wet weight gravimetric basis, this is the method to use with biological horticulture). This might not be necessary, but it's good to know when making compost piles and designing ideal soilless media for cannabis and soil food web.

?.Write. 2008
"[Calculate] Soil Moisture and Soil Organic Matter". Duke, U., Biology Dept.

^^^That short how-to is taken from the following paper. If anyone has trouble opening it I also uploaded it as an HTML webpage at ZohoViewer HERE :

Storer, D. A. 1984.

A simple high sample volume ashing procedure for determination of soil organic matter. Commun. In Soil Sci. Plant Anal. 15(7): 759-772​

Step 3

Separate the sources of Co2 emissions of those from the soil food web visa-vie decompositions of OM (organic matter; e.g., "SOM" for soil OM; or "MOM" for media OM) and Co2 emissions from the roots and rhizosphere:

James W. Raich and German Mora. 2005.

Estimating Root Plus Rhizosphere Contributions to Soil Respiration in Annual Croplands. Soil Sci. Soc. Am. J. 69:634–639 (2005). doi:10.2136/sssaj2004.0257​

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Let me know if you need more info, thanks, I really like have people to work with and learn from (that goes for you too MM, CTGuy, CC, et al.,).

GL

 

[Clackamas Coot]

Hmmm, good idea, does it allow water to pass easily? (edit: I think there are different 'grades' correct?)

secondtry

Most (maybe even 'all') of the landscape products (the commercial at least) that I've seen at trade shows do allow transfer of water.

The SmartPot Auto Pruning pots used by tree growers around here are made from a specific blend that is available in 500' rolls - LOL

At any rate, stick with the ones used by the manly-men of nursery stock operations and your experiment will go as you hope.

HTH

CC

 

[secondtry]

Hey CC,

Thanks for that. I was wondering tho how easy the water passes, not if it passes. I guess it's kind of a dumb question as it probably passes pretty easily. Nvrmnd my daftness, he. Thanks.

The one main reason I like cheesecloth is it would hold less heat and be more breakable. Also it allows filtered light to reach media surface which I think is probably a good thing, but that's only an assumption on my part.

Thanks, I'm getting super stoked to reach OR!

 

[Clackamas Coot]

secondtry

Check out these prices at Concentrates up in Portland near downtown.

Note: This is a PDF - some folks don't like downloading PDF files so I thought I should warn you.

At any rate if you do download this file, scroll down to the products for mixing your own potting soil, organic loose coconut coir, organic peat moss, pumice (all 3 sizes), seaweed extract, seed meals, mineral products and most are prilled - YAY! and are not pelletized. You know the difference Im sure.

Yep - you're gonna love Orygun!

CC

 

[guest2012y]

secondtry

Check out these prices at Concentrates up in Portland near downtown.

Note: This is a PDF - some folks don't like downloading PDF files so I thought I should warn you.

At any rate if you do download this file, scroll down to the products for mixing your own potting soil, organic loose coconut coir, organic peat moss, pumice (all 3 sizes), seaweed extract, seed meals, mineral products and most are prilled - YAY! and are not pelletized. You know the difference Im sure.

Yep - you're gonna love Orygun!

CC

When my Mrs. went there they gave her a price list to keep. She said they were very friendly ,and helpful....I think this is my new favorite place.

 

[Clackamas Coot]

When my Mrs. went there they gave her a price list to keep. She said they were very friendly ,and helpful....I think this is my new favorite place.

They've been around for 72 years - same family still owns it.

Great people and taking advantage of their 'torn bag' deals you can end up with some interesting stuff. That's how I ended up with 4 c.f. of organic rice hulls spread everywhere. What a mess!

CC

 

[secondtry]

Hey,

Great thanks, I'm downloading now. I can tell I will like it by the number of 'good' pet food stores...that's always a good metric IMO. I had to get renter insurance up the ying-yang to appease my realtor to rent to me with two big pit bulls. Is that your puppy in your sig?


That other store, something like EarthFort you told me about looks good too. How is the composting scene in your area? I rented a house with a big back yard but that's for the dogs. Down here I have rented acreage on people's empty land, and even big yards to compost, garden, ensil, etc. This coming summer in OR I want to start windowrow composting to make very high quality compost as I described in the "all about guano thread", but I need room. So I want to rent a little space to compost, is that unheard of? I.e., 'renting the back 40'?

FWIW:
I want to buy this great alternative to a Luebke compost tuner, it's called the "mighty mike" and it's a tow behind compost turner with watering setup, I also need a small tractor to tow the mighty mike. I will make phospho-compost and make high quality compost using my (IMO improved) method of CMC. If you or people you know are interested in going in on a group purchase for the mighty mike and a small (used) tractor we could all compost at the same spot and all make amazing compost, saving us all a lot of money in the long run and provide *much* better compost.

I have to re-read "On the road"!

 

[Clackamas Coot]

secondtry

Honestly I don't know of anyone with 1 acre or more that doesn't have some kind of compost going on. Worm bins are mandatory and some folks (like myself) also do some commercial-level bokashi composting of chicken poop, fish scraps, etc. in 50-gallon trash cans.

Renting fallow acreage is very, very common for the reasons that you're asking about, i.e. composting, windrow worm grows, etc.

Once you're settled in I can meet with you and take you around Eugene and Corvallis and introduce to suppliers, soil mixing operations, prilling operations, etc. Getting an OAN card (Oregon Association of Nurseries) is a good idea as it gives you 'wholesale buying' opportunities. Well worth it, IMHO

I can tell you this - IF you produce high-quality thermal compost there IS a huge market in and around the Central Willamette Valley.

RE: EarthFort - there is 'some' kind of relationship between EarthFort and the folks at the Soil Food Web. As a matter of fact, SFW has their offices in the same suite as EarthFort.

For what it's worth.

HTH

CC