Plants don't care where their nutrients come from. I have used and use both powdered & liquid chemical fertilizers as well as organic things like bone/blood meal and fish/seaweed fertilizers. I can't see much difference, but I tend to favor the fish and seaweed emulsions for outdoor use, but I think the chemical fertilizers work faster. The biggest challenge is getting the micro-nutrients plants need. Potting soils are usually sorely lacking in the minors. The organic emulsions seem to do a pretty good job of it, but I see there are some chemical mixes out now by the bigger fertilizer manufacturers that contain the minors too.

Just got 2 gallons of different mixes of fish emulsion today, BTW. ;o)

Al

Yup, those bacteria are everywhere. I initially started out with using chemical ferts. as a fallback option for my containers but now I don't need to. In your warm climate there is no obstacle to using organic ferts. in containers.

I use peat-moss based potting soils that have been pre-adjusted to pH 5.5. Among the stuff in my fertilizer regimen are seed meals, coffee grounds, wood ashes, composted cow manure and, plenty of compost mixed in with the potting soil prior to planting. I require the wood ashes b/c of the peat moss & acidic seed meals. I mix the ashes in several weeks before planting, as well as with the coffee grounds and seed meals every month or so. However, I would be careful with ashes in any other potting soils. All your suggestions (including bone meal) are great. Good luck! By the way, I mix seed meals & wood ash with water and let it stand for 12-24 hours to get a thick liquid which I pour onto the soil. Bone meal should be directly incorporated under the soil.

In contrast to DrHorticulture's preferences, I have eliminated the use of high percentages of peat, compost, seed meals, coffee grounds, and wood ashes (also high in metal oxides & soluble salts) in my soils, but I see he uses a leachate from some of these materials to water/fertilize, which I haven't tried, relying instead on the commercially organic & inorganic products readily available. The short reason I don't use these soil components is they are either already too fine to suit me or they break down into fine particulates in short order, compromising the aeration/drainage I jealously guard.

Though a pH of 6 - 6.5 is about ideal in containers for a high % of plants, it is extremely difficult (stopping just short of impossible) to maintain any sort of constant pH in containers, especially for hobby growers like us because pH changes quickly as peat & other soil components break down. More important than soil pH is the pH of water we use, which usually has a greater o/a impact on media pH than initial media pH.

Al

Al, jd, DrH, Thank you very much for your replies!
DrH:
"Bone meal should be directly incorporated under the soil."
Is that because bone meal is slow release? Would kelp meal, alfalfa meal work best as leachate or scratched into the potting mix?

Al:
"...break down into fine particulates in short order, compromising the aeration/drainage..."
I didnÂt think about that. Thanks! I can see how fish emulsion and seaweed extract together would make a good complete fert...just wish they werenÂt so expensive (especially when we have so much fish and seaweed here). What would you recommend for a good calcium boost (for tomatoes)?

Has anyone tried this slow release organic fert? http://elawngarden.com/item.php?itemID=145
They also have a non-container version, which I bought by mistake (since I didnÂt know about the container version), and IÂm wondering what is the difference between the container and non-container versions.
Also, would it be good or bad to mulch containers with chopped up fresh seaweed or alfalfa?
Any thoughts on using compost tea in container plants? IÂve been brewing a batch every week, but cannot say itÂs been worth the effort.
Has anyone tried EM or EM-Bokashi? http://www.emtechnologynetwork.org/~en/_web/library/leaflets/activatedEM/aemLeaflet_1.html

Al ... "What would you recommend for a good calcium boost (for tomatoes)?"

How about crushed limestone (calcium carbonate) used as a mulch or crushed eggshells? The lime that is often sold for lawn or garden application is very high in Mg & can create problems in containers by interfering with uptake of K.

Al

Honu,

Yes, bone meal is slow release and will dissolve only under acidic conditions. Eventually bone meal will provide plenty of calcium for your plants but like Al said you can also try some crushed limestone. You most certainly can scratch the other stuff into the soil as well but I simply didn't bother with it b/c it is so time consuming with a lot of containers. By the way, I didn't strain the leachate, I used the whole thing- sediment and all. Converting to a sort of semi-liquid form made it easier to apply.

RE: drainage. I live in a hot, dry climate, so this is less of an issue for me.

By the way what potting mix are you using? If it's something with a pH below 6, then you can incorporate limestone or bone meal before planting and not have to worry too much later about whether your tomatoes are getting enough calcium. Al made a good point about water pH. I've never given much thought to it because our water here is neutral and very low in dissolved ions.

Al & DrH, Thank you again very much for really helping me to understand it is more that just which fert to use.
Al: Thanks for the mulch suggestions. I have some coral rock that I will try as mulch. Is salmonella a concern on eggshell mulch? Should I microwave it or something?
Also thanks for the lime info and for making me think about pH. I didn't realize lime and Mg could cause problems w/ K uptake.

DrH: Thanks for pointing out bone meal needs a low pH. I should check the pH in my pots. I use Gardener and Bloome organic planting mix (not potting soil, because it's more expensive), with some cinder added for drainage. I also use the same brand compost to mulch the tomato pots.

This is my first year growing vegetables in containers. I use organic fertilizers. "Down to Earth" All purpose (monthly application) & foliar feed weekly with fish/kelp/yucca (1/2 application). I can't belive how prolific the tomatoes are!

I am experimenting with tums this year for calcium. I ground it up in my blender. I apply monthly at the base of the plants. I also save all my eggshells for the tomatoes. I just rinse them.

silybum, Congratulations on having prolific tomatoes! What's in the Down to Earth, what strength, and how large are your containers and what type tomatoes?

I used assorted feed meals (alfalfa, kelp, cottonseed, bone, blood, fish, etc.) and greensand in my container soil mix when I lived in Kansas. It worked great. The only reason I don't do it here in (more urban) Nevada is that I can't find the 50-lb. sacks of those assorted feed meals, even at feed stores! Everything is pre-blended as animal feed here. I use slow-release pelleted fertilizer like Osmocote instead, and that's almost as good.

Thanks ljrmiller, I didn't know greensand would be beneficial in containers. Did you use it for perennials, or does it release in time to benefit short-lived crops such as tomatoes?

I use nothing but organic fertilizer in my containers. I mix Espoma Plant-Tone (100% organic) into the soil. For acid lovers I use Holly-Tone (97% organic). I top dress about now with the same thing to keep them happy all summer. Everything thrives, and I've been doing this for years. I use the same stuff on my in-ground gardens, in fact. There are probably other brands out there that are similar. These are what's readily available around here.

It's my understanding that microbial action in the soil is necessary for plants to be able to uptake many nutrients, whether the source of the nutrients is organic or inorganic. The inherent problem with inorganic fertilizers is that they can actually adversely affect (as in kill) those goodguy microbes over time, something many farmers discover to their woe as they futiley apply higher and higher concentrations of fertilizer attempting to get a crop.

The other thing I like about organic feed is it's naturally slow-release. You don't have to feed all the time.

Soeur

Hi, Soeur. Microbial activity is dependent upon the presence of organic matter in soils. Most garden soils, before improvement will contain less than 5% organic matter. The addition of more organic matter supports a larger micro-herd, which in turn, breaks down organic particulates faster making the nutrients available (as long as pH is favorable).

The soils that most container gardeners use are usually 100% organic. The microbes are already there. If, by some chance a decision is made to sterilize container soils, the moment you plant anything other than seeds in the soil, it is inoculated with the microbes. As long as there is a N source, they will continue to multiply, but they are not necessary for plants to be able to absorb nutrients. As long as soil pH is within a suitable range, fertilizers, organic or inorganic, can supply all the nutrients necessary for healthy plants whether microbial activity is present or not.

I'm not promoting the idea that microbial activity isn't desirable, only that it is a minor factor in container culture & merits minor consideration because microbial activity is always ongoing in containers with organic media. Add N, keep moist & suitably warm = expanding microbial activity.

I think the farmer's problem you attributed to the use of chemical fertilizers is more complicated than you make it seem, but that's a discussion for another day. I also don't think there is an "inherent' problem with inorganic fertilizer's use - especially in container culture; perhaps over-use?

Just standing up for those of us who don't attach a stigma to the use of inorganic products. As I mentioned - plants don't care where their nutrients come from, and I've had equally satisfactory results from using both organic and inorganic fertilizer products.

Al

Honu, I use the Down to Earth All Purpose Mix. Contains blood meal, fish bone meal, greensand, Norwegian kelp meal, langbeinite, soft rock phosphate and humic acid. I use 1/3 cup per container each month. Here's the link to my online source.

I have Black Cherry, Green Sausage & Cream Sausage each in their own hanging baskets (16-18") Not very big. At first I thought the plants were getting way to big for the basket, but they are now prolific with fruit and already ripening!

Here is a link that might be useful: Peaceful Valley Farms

Technical error @ end of second paragraph of my last post: organic fertilizers DO require microbial activity to break them down into usable components. Since there is always microbial activity ongoing in container soils, the statement was, in practicality correct, but technically wrong. Sorry.

Al

Al, I am learning so much from you about container gardening. Thanks so much for your excellent and thorough explanations.
Silybum, that Down to Earth sounds like good stuff! Thanks for the link and for translating "5 lbs/100 sf" for a container.
Soeur, Thanks for sharing what has been working well for you.

Honu, I don't know if the greensand released in time for tomatoes, but I just put my mix of meals and greensand in all my containers. Since I toss all my spent potting soil at the end of the year (from the annual containers, at least) into my compost pile or directly out on the garden, it doesn't get wasted, even if it doesn't actually help for short-season plants.

Thanks ljrmiller.