Rookie mistake

[JoeR]

The soil in any pot in the sun can become quite a bit hotter than the general air temperature - the drier the soil, the higher the root temperatures can be; even worse in black plastic pots. Borrow the meat thermometer from your kitchen or buy another dozen (at less than $15 a pop, why not?) and stick it (them) in the roots to see how hot the roots really are.

Minerals are loaded into root cells by an active life process. Water is loaded largely by simple passive osmosis: water goes in if there is less water in the root than in the substrate; water goes in if it is saltier in the root than in the substrate.

Hence, more salt outside the roots draws water out of them = fertilizer 'burn'.


Pretty convincing. I'm surprised that you didn't think to flood the pots. I mean water, water, and water again to flush the fert out when you saw the clear indications after 24 hours. You might still have all or at least some of those 15 or so trees. Ah well, we all have our deer-in-the-headlights moments.

Actually, as soon as I noticed the issue I did flood the pots. I put the hose in and left it there to circulate for probably 20 minutes each. But alas, the damage had already been done. Some of the broad-leafs made it while none of the conifers survived.

Now I only use organic fertilizer (tea bags and fish emulsion) which has proven to be overall much better for my specific needs and schedule.

 

[JoeR]

So how much did you use? What were the weather conditions? Did you apply to dry soil, or did you water first?

We have people (such as Walter Pall) who say they use up to 5x the recommended dose of inorganic fertilizers, so why are a few of you having so many problems?

When the weather is hot I usually fertilize late in the day, after watering. Why...I think if one fertilizes early on a hot day, especially if the soil is dry or the plants are already water stressed, there is a risk of too much fertilizer being drawn into the plant as it takes in water. Or, if the plant takes in water but leaves the fertilizer behind (I'm not really sure how all that works), it is possible the concentration of salts in the container could increase and cause problems. Probably safest would be to cut back the fertilizer rate when it's really hot.

My fertilizer rate is in the range of 1-2 tsp/gal.

I don't remember honestly, but it was early summer so It was hot guaranteed. I applied it and then watered it in (the Ironite stuff that I used wasnt water soluable). I just sprinkled a small amount on the surface of the soil.

With water soluable chemical ferts like the ones Mr. Pall uses, I had no problem using ~4 times the recommended dose. I just couldnt remember to fertilize consistently, so I switched to slow release organic ferts to supply a constant source of nutrients. Just my preference,

 

[Lazylightningny]

I checked the Miracle-Gro spoon: the larger end is 1.5 tbsp and the smaller is 0.5 tsp. I've been using the larger end, somewhat heaping, so let's say 2 tbsp/gal. At a conversion rate of 1 tbsp = 3 tsp, that would be 6 tsp per gallon. Too much?

 

[coh]

I checked the Miracle-Gro spoon: the larger end is 1.5 tbsp and the smaller is 0.5 tsp. I've been using the larger end, somewhat heaping, so let's say 2 tbsp/gal. At a conversion rate of 1 tbsp = 3 tsp, that would be 6 tsp per gallon. Too much?

I don't feel comfortable using that much, but I know others do. @M. Frary, I believe, uses very high rates. Pall says he uses up to 5x the recommended dose. It might be OK if you're not also using the timed release stuff, which releases an unknown quantity with each watering.

 

[coh]

I don't remember honestly, but it was early summer so It was hot guaranteed. I applied it and then watered it in (the Ironite stuff that I used wasnt water soluable). I just sprinkled a small amount on the surface of the soil.

With water soluable chemical ferts like the ones Mr. Pall uses, I had no problem using ~4 times the recommended dose. I just couldnt remember to fertilize consistently, so I switched to slow release organic ferts to supply a constant source of nutrients. Just my preference,

Hmm, ironite...I know I've read somewhere about people having bad experiences (plant damage) with that stuff, though I can't recall the details. You might find some info using google, if you're interested.

 

[sorce]

pipe

Bottle!

@Lazylightningny .....

Any chance you watered with the hot hose water?

Sounds a lot more like something other than fert burn.

Sorce

 

[Carol 83]

Bottle

That's OK then. Carry on...

 

[M. Frary]

I don't feel comfortable using that much, but I know others do. @M. Frary, I believe, uses very high rates. Pall says he uses up to 5x the recommended dose. It might be OK if you're not also using the timed release stuff, which releases an unknown quantity with each watering.

I do. I put 6 heaping scoops with the big end of the scoop to 2 gallons of water. No osmocote. But I apply it at watering time when the plants can sucked up as much as possible. Every Saturday from first sign of green until fall.

 

[aml1014]

I do. I put 6 heaping scoops with the big end of the scoop to 2 gallons of water. No osmocote. But I apply it at watering time when the plants can sucked up as much as possible. Every Saturday from first sign of green until fall.

I also do between double and triple strength every other week during the growing season, that shit has to be ELECTRIC blue lol plus some fish emulsion at regular strength on the opposite week of the MG.
The only chemicals I've cause damage with this year was some bayer systemic. I did about double on accident one day in summer and it took about 6hours for a barberry to be crisp and about a week for my very first jbp I've had for 3 years.

Aaron

 

[GrimLore]

I checked the Miracle-Gro spoon: the larger end is 1.5 tbsp and the smaller is 0.5 tsp. I've been using the larger end, somewhat heaping, so let's say 2 tbsp/gal. At a conversion rate of 1 tbsp = 3 tsp, that would be 6 tsp per gallon. Too much?

If you water first and are using inorganic substrate no it is not to much. One thing I do recommend and do myself is I do not fertilize for the extremely hot two weeks or so when(if you closely watch) the plants are basically not growing at all. As the weather returns to normal heat I resume.

If you are using a rich organic mix I strongly recommend going no more then 2 or a light 3 times the dose on the same schedule including the hot spell.

I don't see not watering and waiting 15 - 20 minutes prior to fertilization AND I never use a slow release at the same time at the rare times I use it. It is rather simple and actually less work then balancing things as many do.

For the record I use Peter's 20-20-20 with micronutrients on most everything except Nitrogen-fixing plants.

Grimmy

 

[Lazylightningny]

Grimmy are you also using poo balls or other organic daily slow-release, or just the weekly Peter's?

 

[GrimLore]

Grimmy are you also using poo balls or other organic daily slow-release, or just the weekly Peter's?

Just the Peter's as it contains everything needed having micronutrients in it. Here is a shot of one growing shelf containing a few types of Juniper, Bald Cypress, Elms, Oaks, Fruit trees, Cypress and more after one season of growth -



For Nitrogen-fixing I use 0 N Grotek or similar.

No Pictures as I did not get any this season.

I have used and still sometimes use slow release formulas on large Tropicals like a 6 foot rubber tree but if I do I don't use anything else. Hell that tree is 18 years old or so and never saw a need for anything else. Funny is I only give it a Spring dose every 2 - 3 years -



Grimmy

 

[Paradox]

I always water before fertilizer.

I don't use miracle grow any more, but when I did, I used a granular miracle grow application early in the spring to get the trees started then did the powder in water at 1/2 strength every 2 weeks to a month.
I didn't fertilize during the very hot months if the trees weren't growing.

Never had a tree die from over fertilizing. If anything, I probably don't fertilize enough.

Now I use only organic.

 

[GrimLore]

Grimmy are you also using poo balls or other organic daily slow-release, or just the weekly Peter's?

I should have added that I fertilize at the surface, not foliar. You could and I have used up to 7 times strength on plants in total inorganic mix going foliar but it was in my experience a waste.
Also, some plants like Quince, Cotoneaster, boxwood and other shrub types I fertilize at a normal dose and only three times a season. What I find with shrub types is they grow sturdy with closer nodes rather then leggy.
I think that covers it except for the indoor stuff during Winter but feel free to ask if need be.
And - mileage varies, this is what I find best for vigorous plants where I live.

Grimmy

 

[sorce]

weekly Peter's

Sounds like the "Monthly Shave Club" for promiscuous women.

Sorce

 

[BrianBay9]

You all check the temperature of the water coming out of your hose on a hot day? Mid day in the sun, the water left in the hose will reach more than 150 F. I asssume nobody is dumb enough to start watering trees without letting the hose run a bit, but I was surprised the first time I noticed how hot it can get.

 

[M. Frary]

You all check the temperature of the water coming out of your hose on a hot day? Mid day in the sun, the water left in the hose will reach more than 150 F. I asssume nobody is dumb enough to start watering trees without letting the hose run a bit, but I was surprised the first time I noticed how hot it can get.

I let it run until it's cold.

 

[Lazylightningny]

I let it run until it's cold.

Same here. It gets mighty hot.
So my conclusion for this thread is that:

• I didn't water plants first. I think this is a good idea, but I was on the fence about it in the past. On the one hand, I felt like it would dilute the fertilizer. On the other hand, it opens the water absorption "channels" in the roots to prepare for nutrient uptake.
• I fertilized mid-morning when temps were already well above 90.
• I was fertilizing at a rate higher than recommended, in addition to having added Osmocote as well. Osmocote release spikes dramatically in temps over 90, so this added to the salts in the soil.
  

  Bottle!
  
  @Lazylightningny .....
  
  Any chance you watered with the hot hose water?
  
  Sounds a lot more like something other than fert burn.
  
  Sorce

  No, I always let it run cold first