Ask a Question forum: when to fertilize

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Name: tk
murchison texas (Zone 8a)

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texaskitty111
Mar 3, 2014 12:27 PM CST
I am really really trying to improve my soil organically, but till then, I have to fertilize. My problem is I seem to be unable to tell what a vegetable plant needs by looking at it. I would have bet a heirloom tomato plant that my veggies had too much nitrogen, not enough other needed elements. They were huge, weak, blossoms were not setting. So I sent in a soil sample, and to my surprise, I was lacking in nitrogen, and everything else EXCEPT phosphorus, which I had way too much of ( too much goat and chicken poop? ) I'm not supposed to add any phosphorus for 5 years. (No more goat and chicken poop for 5 years?) So, I have been spraying them with ironite, as it has what my plants need. ( have to spray as phosphorus keeps nutrients from being absorbed) Anyway, my question is, since the instructions say to spray it on every 2 - 4 weeks, and its expensive, how do I know if I'm spraying enough or too much? The plants did look healthier after 2 weeks last year, but I still got no tomatoes. I sprayed every 3 weeks last year.


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Name: Elaine
South Sarasota, Florida (Zone 9b)
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dyzzypyxxy
Mar 3, 2014 1:32 PM CST
Wow, avoiding the addition of phosphorus definitely limits your ability to fertilize with a commercial product, doesn't it! We have phosphorus naturally in the soil here, but its not usually enough to cause problems. But the specially formulated "Tomato Fertilizer" products seem to always have a high middle number in the analysis. If you're using the Ironite Mineral Supplement, it's a really low analysis at 1 - 0 - 1 ! Might need to supplement it, maybe ammonium sulphate (cheap lawn fert is usually this) would help keep the plants going.

Another nutrient that's cheap and easy to apply by itself is magnesium. Ironite has a magnesium component but it is a trace amount. I'd try a teaspoon or two of Epsom Salts in a gallon of water on some of your plants and see what it does. Can't hurt. It's made a world of difference to my brugmansias and orchids, and I'm trying it on my tomatoes in my Earth Boxes. They seem to like it so far after one dose.

If you can come by some compost tea, (pure vegetable material, no manure in it) that also might be a good supplement that's low in phosphorus.

Elaine

"Success is stumbling from failure to failure with no loss of enthusiasm." –Winston Churchill
Name: tk
murchison texas (Zone 8a)

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texaskitty111
Mar 3, 2014 3:33 PM CST
What a great idea. I have been adding the kitchen compost directly into holes dug in my garden all winter, up to March, then switched to the regular compost pile. But, there's no reason I can't make a tea first and pour around the plants. Anyone know how close to a commercial fertizer that is? (Usually citrus peels, banana, coffee, tea) Do I need to use it sparingly, or is it mild?
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Name: Joanne
Calgary, AB Canada (Zone 3a)
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Joannabanana
Mar 3, 2014 4:12 PM CST
I would try a liquid fish emulsion fertilizer and add Epsom Salts as well.
[Last edited by Joannabanana - Mar 3, 2014 4:13 PM (+)]
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Name: Reid
North Branch, MN (Zone 4b)
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Anderwood
Mar 3, 2014 4:14 PM CST
Try the products from Gardens Alive! company. Keep up with the compost. Do you garden in flat grounds, or raised beds? I would advise using raised beds with a mix of high quality compost and topsoil. If anyone has leaves left over from last fall, add about 20% coffee grounds to them, and it will make the best compost around. This is all the nutrition your plants will need. Apply a two inch layer on top of the soil. Good luck. Keep updated during the growing season.
Name: Horseshoe Griffin
Efland, NC (Zone 7a)
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Horseshoe
Mar 3, 2014 5:44 PM CST
T-kitty, did your soil test actually mention a shortage of N, or did it not include nitrogen in the test? The reason I ask is most soil tests don't include it because it is so soluble and variable, depending on soil types, temperature, time of year, etc. As for Ironite it is very low in N and in most cases tends to play a cosmetic role, normally used to green up foliage but not contributing to foliage growth.

Keep in mind also that compost/leaves/yard waste tends to offer phosphorus as well so you may want to use it sparingly.

Oh yeh, what pH did your soil test show?

Shoe

Name: tk
murchison texas (Zone 8a)

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texaskitty111
Mar 3, 2014 6:53 PM CST
Thanks for all the help.

My soil test 2013 was:

PH. 7.8
Nitrate 25
Phosphorus 212
Potassium 303
Calcium 1152
Magnesium 259
Sulfur 12
Sodium 23
Iron, zinc, manganese, copper, boron I don't think were tested, however in 2007, they were all high too

Since most elements were too high only recommendation was apply nitrogen once a month and do not apply phosphorus for 5 years.

I have been trying to correct the problem for the last year, but have not had soil tested in 2014. In 2007, nitrogen was 3, so there has been some improvement there. BUT pH in 2007 was 6, so it seems I can't win. (PH done with a store bought tester is now 6.5)


Cauliflower is just a cabbage with a college education (mark twain)
Name: Elaine
South Sarasota, Florida (Zone 9b)
The one constant in life is change
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dyzzypyxxy
Mar 3, 2014 6:54 PM CST
True the pH makes a big difference to nutrient uptake, as well.

Fish fertilizers all have some phosphorus so read the label to get the least, if you use it. I gave up using it years ago when I'd have every cat, dog and raccoon for miles roaming my yard until the smell went away. Even the supposedly less smelly 'deodorized' stuff still stinks a lot, jmho.
Elaine

"Success is stumbling from failure to failure with no loss of enthusiasm." –Winston Churchill
[Last edited by dyzzypyxxy - Mar 3, 2014 7:02 PM (+)]
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Name: Rick R.
near Minneapolis, MN zone 4a
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Leftwood
Mar 3, 2014 8:16 PM CST
Many states have laws that do not allow phosphorus in lawn fertilizer (maybe Texas, too?). Consequently, they are very high in nitrogen, no phosphorus and a little potassium. Usually, the analysis is something like 30-0-4 (percent by weight of nitrogen, phosphorus and potassium).

If those are your tomato seedlings in your pic, I don't see any definite symptoms of fertilizer deficiency, although one can't tell for sure. To me, they look like they could use more light and/or larger pots.
Name: tk
murchison texas (Zone 8a)

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texaskitty111
Mar 3, 2014 8:44 PM CST
No, those are not mine, just a pic of too much nitrogen. I have been using that lawn fertilizer. Supposedly though, plants can't absorb nutrients if there is too much phosphorus. Those plants do look like somewhat like my tomato plants in 2013 though. Long branches, weak, no fruit.
Cauliflower is just a cabbage with a college education (mark twain)
Name: Elaine
South Sarasota, Florida (Zone 9b)
The one constant in life is change
Cat Lover Master Gardener: Florida Tropicals Multi-Region Gardener Vegetable Grower Region: Florida
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dyzzypyxxy
Mar 3, 2014 8:52 PM CST
No way to tell how rich your compost tea is, unless you know somebody with a chem lab? But it still would vary with each batch, according to how much and what was in the compost and how much you diluted it.

You might designate one plant as a test subject to see if, and how much you need to dilute the compost tea. It's probably not high in nitrogen in any case because nitrogen is used in the composting process. Supplementing with the cheap lawn fert is going to be your best bet for keeping your veggies fed, I'm afraid.

Soil testing is pretty variable, too and as somebody said above, the nitrogen is so soluble, the reading would vary from place to place in your garden, and also by season. In spring when the soil has been 'resting' all winter and you've been amending with your compost, it might have a higher N component than after you've been watering all summer, or even after a few heavy rains that would wash/leach out all the soluble components.

Have you considered planting a cover crop of some legume? They 'fix' nitrogen in the soil, I forget how it works, though. Anyway, you plant something like vetch or cow peas, let them grow a month or two, then till them under and plant your spring garden. I think organic farmers use this system to renew their soil, planting the cover crop in fall after the main crop is harvested.
Elaine

"Success is stumbling from failure to failure with no loss of enthusiasm." –Winston Churchill
Name: tk
murchison texas (Zone 8a)

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texaskitty111
Mar 3, 2014 8:59 PM CST
I considered vetch, but it seemed too much work to me.
Cauliflower is just a cabbage with a college education (mark twain)
Name: Horseshoe Griffin
Efland, NC (Zone 7a)
And in the end...a happy beginning!
Charter ATP Member I helped beta test the Garden Planting Calendar Hosted a Not-A-Raffle-Raffle Garden Sages I sent a postcard to Randy! I was one of the first 300 contributors to the plant database!
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Horseshoe
Mar 3, 2014 9:23 PM CST
Well, from my perspective, going from your soil test of 2013 your soil pH of 7.8 is tad high and will not allow a whole lot of phosphorus to become available to your plants; perhaps that contributes to it building up in your soil. If your home pH test is accurate then you'll be on the right track, at a level when more major nutrients as well as trace/micronutrients will be available to plants. As for the ironite, I think you're going to get locked into weekly sprays for it to benefit your plants and deficit your pocketbook. But whatever works.... I really wonder if you'd be better off using "Cal-Mag" which would give you a decent amount of N, K, and a smaller amount of P, and being water soluble would more readily benefit your plants.

Shoe

Name: Rick Corey
Everett WA 98204 (Zone 8a)
Sunset Zone 5. Koppen Csb. Eco 2f
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RickCorey
Mar 4, 2014 12:46 AM CST
If you're sure you're very low in N, and can't add any P, there are "industrial-strength chemical fertilizers" that are all-N.

I have a big bag of urea (46-0-0, I think). Per pound of nitrogen, it is very cheap. However, it has to be the easiest thing in the world to over-do, and the most likely to burn plants if used to excess.

I'm far from sure I would recommend it, but if dissolved and diluted, it sure will add N to marginal soil. Much better to have rich organic soil with all nutrients present in slow-release organic form, if you can.

Excessive chemical fertilizers (especially high-N fertilizers) are kind of harsh on root hairs, leaves, soil microbes and probably worms. I rely on lots of dilution, and under-fertilization.

If you're interested, I'll look up the numbers suggested for safe application rates. Ideally, you would dissolve a little in a bucket, and then use a 20-1 dilution mixer/sprayer. Otherwise, dissolve a very little per gallon, and spread it with a watering can.

It might be safer for plant root hairs and soil microorganisms to dilute household ammonia (if you find a brand with no perfume or other additives). I don't know the numbers for safe dilution of ammonia.
Name: tk
murchison texas (Zone 8a)

Tomato Heads
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texaskitty111
Mar 4, 2014 7:21 AM CST
I have a hose sprayer and would like to know what number to set the dial in order to spray the plants, and how often. Where did you buy it? Never seen it around. I have been using lawn fertilizer without phosphorus.
Cauliflower is just a cabbage with a college education (mark twain)
Name: Rick Corey
Everett WA 98204 (Zone 8a)
Sunset Zone 5. Koppen Csb. Eco 2f
I helped beta test the first seed swap Plant and/or Seed Trader Seed Starter Region: Pacific Northwest Photo Contest Winner: 2014 Vegetable Grower
Avid Green Pages Reviewer Garden Ideas: Master Level Garden Sages I was one of the first 300 contributors to the plant database! I helped plan and beta test the plant database. Charter ATP Member
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RickCorey
Mar 4, 2014 3:02 PM CST
What I found was an $18 "Hozon Siphon Mixer", and I found it in a local place: "Steuber's Distributing".

That doesn't come with a spray nozzle.

You might try putting in a measured amount of something , picking an intermediate setting, and then seeing how long it takes to suck the jar empty.

That won't work if it's like a Miracle-Gro sprayer I had once: it continuously dilutes whatever you spray with.

If the amount it delivers can't be determined, I would be very cautious about using it with any highly concentrated fertilizer. Better to mix a few gallons and water by hand with a wtaering can, or just using less-concentrated fertilizers.

Hopefully you can thin out the excess P in just a few years. Would it be practical to create a few new beds, then divide your current soil among them, and then top them all off with several cubic yards of new soil? [s]Or just truckloads of compost? [/u] (To dilute the excess P faster.)

Does anyone know of a very heavy feeder that takes up a lot of Phosphate?

Edited to add: Compost adds P! Manure adds even more P. Be careful about adding compost when you already have excess P.

[Last edited by RickCorey - Jan 7, 2015 12:18 PM (+)]
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