which fertilizer, plant food?

I have used spray n grow, miracle grow and various other fertyilizers/plant foods. The evidence for their products are personal testimonials. Does anyone know whether legitimate studies have been made of the relative efficacy of these products? Without such studies, how do we know what to use?

I can guarantee that the brands like Miracle Gro that are owned by larger companies have more than personal testimonials backing them up. The FTC regulates advertising, and the large companies will challenge each others' ads if they think somebody's lying, so any claims that they make are backed up by some sort of actual data which their lawyers believe would stand up in court if someone were to challenge the ad or if the FTC were to come sniffing around. That's not to say that their data is perfect, but at least there's something there to back up the claims. The smaller companies tend to fly under the FTC's radar a bit more, and the larger companies don't care enough about them to challenge their claims in court, so I'd trust those a little less unless they have info on their website that provides something more than personal testimonials.

the only way to really know what to use is to understand PH, macro and micro nutrients, base vs acidic fertilizers,what type of growing medium you are growing in as to what kind of nitrogen you need, what strengths (ppm) to use on what size plant and to know what are the particular needs of the plants that you are feeding-i.e what PH they need and any extra micro nutrients that they might benefit from.
It sounds a bit complicated, but it helps alot to know some of the above at least, and isn't that hard to understand when you jump in and start to learn about it.

Tigerlily, do you have suggestions as to where to start with that? A book, a website?

Pagancat, I don't really know where to start with that-except to start googling things like " PH needed for annuals" and see what you get, or substitute perennials or woody shrubs etc if that is what is of interest. Also "macro and micronutrients in fertilizer" or google "fertilizer needs for petunias" etc. Also "ammonical and nitrate nitrogen and soiless mediums"

I have picked up the vast majority of my knowledge through growing commercially-where you have to know what you are doing if you want to pull off the crop! lol I assure you that my first year or two was alot of trial and error and learning from mistakes. I get a lot of trade mags and I have a lot of books that were written for commercial growing. They are pretty technical, and probably not good to start with.

I wish I had the time now to write a few articles on it, but I am right in the middle of a crop and tired! But please feel free to read some and come back and ask questions. Its easier to answer questions for me than to write an article right now. Maybe in my off time in June I can do some writing.

Seems to me that tapla has a thread either on the container forum or the indoor gardening and houseplant forum where he talks about this--you might check those out and see if you find what you need. I don't think he recommends specific brands, but he talks in general about how much plants need of certain things.

Thanks to all of you for your input. Until now, I have followed the "survival of the fittest" model. That means every spring, I dump a few bags of composted manure on my soil and then apply something like miracle-gro throughout the summer. Tomatoes, peppers, pole beans, most herbs and lettuce do fine - But all I get from cucumber are vines.

My concern about providing each seed with what it needs is that I would then have to isolate part of my garden - high PH, low PH, etc. It would be great if someone were to write article saying "for this group of vegetables and flowers, kick the PH up a bit, for these, lower it, and for another grouping, add something else." This wouldn't be perfect, but it would probably make a big difference.

I got ya, emorss - I think many (if not most) of us do the survival of the fittest trick. And I think many plants have a range of what they can tolerate, so we usually get kinda lucky, if we hit a middle ground.

I had a real boost in my knowledge of pH balance when I moved to the desert southwest - the soil is very alkaline and perfect for what grows there, but not so hot for what I had been used to growing. I'm the type of gardener who wants things to thrive vs. just survive, so I adapted my plant palette to match. Now I'm in the top of the southeast and back to being clueless (lol!).

I also prefer to use fewer additives when I "fertilize", trying things like composted materials, using nitrogen-fixing plants, etc. - less work, less expense, less impact on my corner of the world.

You could quickly google each plant for PH and probably come across a chart for all of the vegetables, annuals etc.

I was thinking more along the lines of fertilizering containers before. I gather you are growing organically or would you use a slow release fert? Do you know what the PH of the soil is in the garden?

It sounds like most of your things are veggies, you might also try looking around the vegetable gardening forum, you'll probably find lots of the info you're looking for there. (And you might try browsing through the articles too--it wouldn't surprise me if someone has written a veggie growing article or two that may have exactly the info you're looking for)

By law all products sold as fertilizer must list the N-P-K ratio.

"Spray n Grow's" is 0-0-0. It has no appreciable nitrogen, phosphorous or potassium in it.

Never tried it but it seems to me, a plant in a soiless potting mix and "fertilized" with "Spray n Grow" wouldn't last long.

The fertilizer effect, if any, must be micronutrients enhancing the basic elements plants need to live.

The "Spray N Grow" guarenteed analysis is here:

http://www.spray-n-growwholesale.com/Grower%20Packets.pdf

My soil certainly isn't the same but I bet I have more than 0.024 parts per million of barium, 0.647 parts per million of molybdenum, 12.840 parts per million of copper etc...etc...in my soil already.

I know I have more than the 0.676 parts per million of phosphorous "Spray N Grow" has in its product in my soil. The state lab told me I was low last year and I had to put in 60 pounds of 10-10-10 per 1,000 sq feet to bring it up to an optimum N-P-K level.

Before I pay a hundred bucks a gallon for a product which contains common elements in minute amounts, I would like to see some double blind comparison studies by independent labs as well as the research the company did to discover these exact ratios enhance plant growth.

Edit: looking over "Spray N Grow" guarenteed analysis I see the highest level of anything is 5110.0 parts per million of sodium.

Last year I used Baking soda (Sodium bicarbonate) to control powdery mildew. It burned the leaves if not diluted correctly (which I didn't do correctly some days). Doubt "Spray N Grow" has enough in it to do anything but sodium is nothing I really want to put in my soil. Not living a mile from the beach. This year I've going to potassium bicarbonate (a little more expensive) to control mildrew.







This message was edited Feb 19, 2008 12:58 AM

I have used foliar fertilizers for years now, and I do grow a number of things to produce seeds for sale. I don't use any synthetic ferts, and I have actually never tested my soil, but I still get good growth. I've had really good luck with liquid kelp, fish emulsion, and various versions of what is something like compost/manure tea that is standardized in terms of NPK. You can get different formulations for different purposes--to encourage leafing, bloom, or roots. I use the Omega brand plus whatever kelp is convenient. Right now I am using Maxi-Crop, which you get dried and it dissolves right away, very convenient and good for shipping. I had suspected that kelp spray helped keep some bugs off, since I kept seeing this in my plants, and recently I saw references to some studies that showed it helped keep aphids and other stuff off. It does get kind of overwhelming, all the different fertilizers. I stick to these few plus adding compost to the soil and it works for me. This year I will be trying underplanting with clover and such as well.