How much do I need to fertilize large outdoor plants?

[lazyfish]

Hello Everyone,

I have a large 6 foot outdoor plant and it has started showing yellowing leaves and burnt tips at the lower mid and close to the top sections of the plant. When I first noticed this two weeks ago I gave it a foliar spray with seaweed extract (micronutrients) and fertilized with a (0.15-0.85-0.55) all purpose fertilizer. A week later I gave it a foliar spray with epsom salt (magnesium sulfate, MgSO4) and gave it a half dose of (5-1-1) fish emultion. I've never grown plants with large before. Indoors I would flush, foliar spray, and fertilize and the problems would go away.

Can I flush plants outdoors when they are in the ground?

I'm afraid I might not keeping up in the fertilizer department but I don't know what the dosage is like with plants this large outdoors. I want to just start giving it a double dose of some strong nitrogen (N) fish emulsion fertilizer but I'm afraid of burning it.

Please any input would help settle my mind.

Most of the damaged leaves are mostly in the interior of the plant.

Please and thank you,

 

[Ganja God 420]

I would recommend investing in cannabis-based nutrients because they will have everything your plants will need to stay happy and healthy. I would also recommend using nutrients more than once a week. If you give them smaller amounts of nutrients once every 2 days, watering with plain water between nutrient rich waterings to prevent nutrient buildup, you will avoid burning them and should solve most of your nutrient problems. Hope this helps, and good luck on your grow!

 

[lazyfish]

So, I think it might be a Magnesium or Zinc deficiency due to lockout from an overdose of Potassium Hydroxide (KOH) which is what is in General Hydroponics pH UP solution. I use approximatly 5.0 mL per gallon of fertilizer. I can't tell how much Potassium this adds, but is seems like it would be a lot when I am mixing 2 or three gallons of fertilizer per week.

Are there other easy ways to raise pH? Can I use Calcium Carbonate?

 

[brightlight]

Hey lazy fish....the mottled green leaves are Mg deficiency. Plus I see the start of purple on a petiole, also sign of Mg shortage on outdoor plants. I use langbeinite, organic mineral that will give you K, Mg, & S. Available at most garden nurseries. You should not have any pH issues growing outside in soil.

 

[Lester Freeman]

When you have a big 6 foot plant, you expect a few messed up leaves here and there - nothing is 100% perfect in nature, nothing.

You'll often see bug bites and bits of "fussyness" as I like to call it. Not to worry - usually just because you have a few odd looking leaves doesn't mean there is a huge problem to go fix. Sometimes less is more. We would have to see the status of the entire plant to be certain it's not a pathogenic ordeal.

When plants get old, the oldest leaves often times die, they don't stick around forever, the plant makes calculated decisions usually about what its doing, sometimes killing of several leaves and harvesting the energy stored inside them. Stick to all organic ready-made fertilizers and one general rule of them whenever you are feeding some kind of nutrient solution. Do not feed the nutrient solution to a dry soil, the plant roots have to be watered with fresh water first to prevent leaf tip burning.

In general you should not be or need to be flushing plants that are in the ground, and I would not be concerned with messing around with pH at all. What does the whole plant look like?

 

[Lester Freeman]

Hey lazy fish....the mottled green leaves are Mg deficiency. Plus I see the start of purple on a petiole, also sign of Mg shortage on outdoor plants. I use langbeinite, organic mineral that will give you K, Mg, & S. Available at most garden nurseries. You should not have any pH issues growing outside in soil.

It's quite possibly hungry for Mg, depending on the ppm of the water. I tend to disagree with the idea that purple petioles immediately means a for sure deficiency, IMO this is simply not always the case. In many cases, this is just the genetics talking and I've had several specimens with purple petioles that were completely healthy and not deficient.

 

[Emilya Green]

I also suggest that it is simply a magnesium deficiency and starting to show signs of hunger with that dramatic yellowing from the bottom and the interior of the plant. Generally, I feed outside plants at 3x the indoor rate, and you need to get on it. You mentioned burnt tips... those leaves are being cannibalized for their magnesium, that isn't burning. Also, flushing outside in the soil makes no sense, you are just washing away your nutrients.

Might I suggest also getting some of those plant food stakes to put in the soil around the plant? That, some strong feeding and some calmag, and you should be good.

Curious, did you notice a dramatic greening after the foliar spray?

 

[lazyfish]

I have been giving it an epsom salt spray for the past few days and it seems to still be losing health. I use 1 tsp per gallon for spray and also watered with a few gallons two days ago.

Lester, the idea of watering first and not adding fertilizer directly to dry soil is an interesting and sensible point....

Emilya, Do you fertilize with 3x the volume of fertilizer or 3x the strength(concentration)?

Its interesting, I have three other large plants in the same area that I feed at the same rate, and this is the only one that is having any problems. Unless I just don't know what some of the symptoms look like.... None of them are this drastic anyways.

It's strange, only the main stalk of the plant was affected at first. About half of the plant is normal and healthy looking.

Pics:

Thank you all for your time and advice! It really sets my mind at ease when I know that more experienced growers are looking at this problem and giving their two cents. I basically know nobody that grows and have no-one to go to when it comes for a second opinion.

 

[Emilya Green]

3x the strength... extra volume will just run off and end up diluting itself even more

 

[lazyfish]

Hello Everyone,

So a few days ago, before anyone responded to this post, I "flushed" the plant...... basically flooded the outdoor garden with fresh water....I then applied a top dressing of my favorite local outdoor soil mix and watered it in.

I have also applied an epsom salt (MgSO4) spray every other day and applied a (complete nutrient) seaweed extract foliar spray yesterday (8/7/2016).

I am having a hard time distinguishing whether the plant is improving or not. I think that the yellowing of the leaves has slowed but it is hard to keep track.

I have been thinking about what Lester said about making the soil wet before a fertilizer is applied. This makes a lot of sense (and I wonder about all the times my puppy urinated near the plants). I have kept this in mind when watering other plants. I have not yet watered the plant in question because the weather has been quite cool and wet since the "flush".

Does anyone believe it might be a Magnesium lockout due to a Potassium toxicity from the overuse of KOH to raise the pH?

Thanks for all of your time and positive energy.

lazyfish

 

[Emilya Green]

Stop being so timid with this giant plant. She can handle some heavy feeding and needs it, quick. You can keep squirting nutes at the leaves if you want, but if you think that is going to get you ahead of the game with such a big plant, I am afraid that you are mistaken. The roots are there for a reason... use them. Feed heavily. 3x the indoor rate... Put your squirt gun away, and really give them some food and stop insisting that it is a lock out... the only lock on that door is your reluctance to really give it to her good. On top of that, you flushed.

no, i dont think that is is a magnesium lockout due to potassium toxicity. It looks like a classic starving and magnesium deficiency to me.

And... you have been doing it your way and have seen a "slowing of the yellowing" so you know you are on the right track. You just can't get it in her fast enough via the leaves. Give her a good stiff drink to wet that soil a bit, chat her up real nice, and then give it to her good. She will like it.

 

[lazyfish]

So...

That might have been just the nudge that I needed.

I just don't really know what I am doing and think I just am searching for reassurance when there is such a huge plant at stake.

Thank you Emilya...

 

[Major PITA]

I'd stop the foliar feeding. It is good for about 10%-15% of what the plant needs, but is more like the icing on the cake. It can also burn leaves. If you have problems or really need to feed it, feed the roots. I'd also change one thing at a time. If you add this, or change that, you have no way of knowing what is helping and what might be making things worse.

I always give my plants water first, then come back and feed the ones that get nute's. You plants look like they could use some well balance fert's. The fishy stuff might give them adequate 'N', but probably not enough of anything else. The all-purpose fert's sounds really low in nute's.

 

[FenderSuper]

I'd try Brawndo. It's got electrolytes. They're what plants crave.

(c'mon, someone had to do it)

 

[lazyfish]

nice!