When to top dress in flower?

Nutty sKunK

Well-Known Member
So let’s say a 10 week strain. When should one do a final top dress?

How long do they take to activate?

cheers
 

Weedvin

Well-Known Member
So let’s say a 10 week strain. When should one do a final top dress?

How long do they take to activate?

cheers
Compost tea ( earthworm tea) I'll use 1-tsp 0-20-0/ gallon/tea. Build a soil has 2# sacks 35$ ea. 16-0-0. 0-20-0 and 0-0-20 ,
 

green_machine_two9er

Well-Known Member
Compost tea ( earthworm tea) I'll use 1-tsp 0-20-0/ gallon/tea. Build a soil has 2# sacks 35$ ea. 16-0-0. 0-20-0 and 0-0-20 ,
These 2# sacks fertilize one acre.
Ummmm that makes perfect sense. Great !
So let’s say a 10 week strain. When should one do a final top dress?

How long do they take to activate?

cheers
I like to get food on top 2 weeks ahead of time. Snd I believe it only starts to get active after 2 weeks.

Also depends which amendments your using and how ground or broken up they are.
 

Marq1340

Well-Known Member
So let’s say a 10 week strain. When should one do a final top dress?

How long do they take to activate?

cheers
I vote for sticking to your routine.

Been top dressing twice a week? If it's working I say keep that routine through harvest.

Same goes for once a week.

I figure it'll never go to waste since you'll likely reuse the soil at some point.
 

JustBlazin

Well-Known Member
I usually do About 2-3 weeks prior to harvest.
And like green machine said different amendments take different amounts of time to become available. But usually a week or 2 before anything becomes available for your plant.
I re use my soil so even if I top dress to late it's not to big a deal as it's just going to be available for my next round.
 
Last edited:

green_machine_two9er

Well-Known Member
Right. Top dress pre flower. and once about 2-3 weeks in. This depends on the plants needs and done right you don’t have to add any amendments at recycle snd never have to re-“cook” soils. At harvest just cut at base maybe take the woody pieces or root out and mix-repot- reuse. I do it all in one day if I’m pressed for time.


Not only the nutrients but any compost or ewc topped will now be incorporated into the mix. All good stuff. Sometimes just perlite if needed during recycle
 

Nutty sKunK

Well-Known Member
Right. Top dress pre flower. and once about 2-3 weeks in. This depends on the plants needs and done right you don’t have to add any amendments at recycle snd never have to re-“cook” soils. At harvest just cut at base maybe take the woody pieces or root out and mix-repot- reuse. I do it all in one day if I’m pressed for time.


Not only the nutrients but any compost or ewc topped will now be incorporated into the mix. All good stuff. Sometimes just perlite if needed during recycle
Cheers for the replies guys!

I’m going to simply be top dressing worm castings and bat guano. So will do this at the time suggested.

Thanks again!!
 

Nutty sKunK

Well-Known Member
Just curious, what size pot are you in?
These autos are in 3 gallons. I won’t be top dressing these as they’re almost done. The guano and worm castings were already incorporated which made the soil too hot.

Now my thinking is to top dress as the plants mature as not to stunt them in hot soil.

Next run are photos in 5 gal.

Here’s on of the ladies. Bit of light burn but first time using LEDE5DFBFEF-F82D-4043-96D4-6EFE93F0A901.jpeg
 

kratos015

Well-Known Member
So let’s say a 10 week strain. When should one do a final top dress?

How long do they take to activate?

cheers
Depends on the top dress, but 4 weeks is a pretty good average for those all purpose and bloom organic blend mixes. Naturally, certain things take months to years to decompose, but I'm guessing you're asking about those blends yes? Check the bag, most say re-apply monthly.

However, for bloom, I apply every 1-2 weeks depending on how far along in flower I am. At the beginning of flower, every 2 weeks will suffice, but for those heavy feeders sometimes weekly applications may be necessary after week 4.

The reason those light 4-6-2 or 4-8-4 blends are emphasized is because it is very difficult to over feed with them. Even if you applied those weekly, the worst you'd experience is waste in the form of diminishing returns.


These autos are in 3 gallons. I won’t be top dressing these as they’re almost done. The guano and worm castings were already incorporated which made the soil too hot.

Now my thinking is to top dress as the plants mature as not to stunt them in hot soil.


Next run are photos in 5 gal.

Here’s on of the ladies. Bit of light burn but first time using LEDView attachment 5016406
Guano can definitely make things "hot" with how quickly the stuff decomposes. EWC, on the other hand, will never cause those issues.

Finish this grow out (if you haven't already), and just continue to water only until next flower.

That last photo you posted shows light K def and also slightly excess N.

What is the soil mix you're using? Got a link or something so I can check it out? Be able to give more concrete advice for your situation if I knew what kind of soil you bought and are dealing with.

Based on the color of those leaves, and the size of those nugs, you definitely have plenty of nutrients in the soil, excluding the K of course. Color of those leaves tell me you likely won't need to top dress with more nitrogen for at least a few months, possibly even an entire new plant cycle. Without seeing the soil ingredients, just looking at the plant, my thinking is just to source something that has sufficient potassium in it and top dress with that.

From what I'm seeing though, looks like you shouldn't need a top dress for a while.

Regards.
 

Nutty sKunK

Well-Known Member
Depends on the top dress, but 4 weeks is a pretty good average for those all purpose and bloom organic blend mixes. Naturally, certain things take months to years to decompose, but I'm guessing you're asking about those blends yes? Check the bag, most say re-apply monthly.

However, for bloom, I apply every 1-2 weeks depending on how far along in flower I am. At the beginning of flower, every 2 weeks will suffice, but for those heavy feeders sometimes weekly applications may be necessary after week 4.

The reason those light 4-6-2 or 4-8-4 blends are emphasized is because it is very difficult to over feed with them. Even if you applied those weekly, the worst you'd experience is waste in the form of diminishing returns.




Guano can definitely make things "hot" with how quickly the stuff decomposes. EWC, on the other hand, will never cause those issues.

Finish this grow out (if you haven't already), and just continue to water only until next flower.

That last photo you posted shows light K def and also slightly excess N.

What is the soil mix you're using? Got a link or something so I can check it out? Be able to give more concrete advice for your situation if I knew what kind of soil you bought and are dealing with.

Based on the color of those leaves, and the size of those nugs, you definitely have plenty of nutrients in the soil, excluding the K of course. Color of those leaves tell me you likely won't need to top dress with more nitrogen for at least a few months, possibly even an entire new plant cycle. Without seeing the soil ingredients, just looking at the plant, my thinking is just to source something that has sufficient potassium in it and top dress with that.

From what I'm seeing though, looks like you shouldn't need a top dress for a while.

Regards.
Cheers for the help.

It’s just Guano and EWC I’m looking at, no premade mixes so will probs top dress every couple weeks or so.

Soil mix is really simple. Plant magic soil supreme which is basically peat cut with another batmix blend. House and garden to be specific.

That yellowing is actually Cu def coupled with getting too dry which exacerbated the situation. Every single plant of mine shows Cu deficiency.., quite bizzare but never seems to effect it too much. It did help somewhat putting a copper coin in the soil. She is the only one without a coin lol

My feeding regime has been let the soil and amendments tire out then feed liquid organics. They’re aren’t def in K since no lower leaves are yellowing. Maybe it’s showing they since the light is so intense?

First Time using LED and having a few niggles
 

Three Berries

Well-Known Member
I got some potassium bicarbonate off Amazon from a brewing supply store. It's what I'm using for my current K deficiency. It's a base buffer though.

 

kratos015

Well-Known Member
Cheers for the help.

It’s just Guano and EWC I’m looking at, no premade mixes so will probs top dress every couple weeks or so.

Soil mix is really simple. Plant magic soil supreme which is basically peat cut with another batmix blend. House and garden to be specific.

That yellowing is actually Cu def coupled with getting too dry which exacerbated the situation. Every single plant of mine shows Cu deficiency.., quite bizzare but never seems to effect it too much. It did help somewhat putting a copper coin in the soil. She is the only one without a coin lol

My feeding regime has been let the soil and amendments tire out then feed liquid organics. They’re aren’t def in K since no lower leaves are yellowing. Maybe it’s showing they since the light is so intense?

First Time using LED and having a few niggles
My mistake. I must have glanced over where you said "Bit of light burn but first time using LED" earlier in the thread. Definitely what's happening here, other than that, no issues and keep doing what you've been doing. Just gotta raise the lights a tad is all. You clearly know what you're doing, and what your issues are. These new lights are so intense and different, that those of us coming from Single Ended bulbs have had to learn a lot all over again.

Definite learning curves with these new lights. My DE caused similar issues and caught me by surprise.

I've noticed that I usually have to dim the DE during the last few weeks of flower, even if I have proper light distance. Plants love every last bit of light from those lights right up until around week 5-6 of flower, I've noticed. Makes sense, considering how the sun's intensity and spectrum change from summer to fall.


What is your RH? I used to run 40% with single ended bulbs, but once I switched to DE the plants always looked like shit if RH was below 50%. Especially in flower. Increasing your RH will definitely help with the light's intensity as well.


Sometimes LEDs can cause deficiencies like that on the canopy due to their intensity and spectrum. This usually happens with Mg, but it can happen with K too. Both Mg and K play a vital role in chlorophyll production, and photosynthesis by proxy.

Even though the canopy temps are likely cool enough, the intensity of them can still cause damage on the canopy. Due to the extra spectrum LED/DE bulbs bring to the table, it isn't uncommon to need to bring extra Mg and K to the table to compensate. More photosynthesis = more nutes.

Still some sexy nugs though. Regards.



I got some potassium bicarbonate off Amazon from a brewing supply store. It's what I'm using for my current K deficiency. It's a base buffer though.
Interesting. So do you just use less lime to compensate for the buffering capabilities of the potassium bicarbonate?

I've grown quite fond of Langbeinite this past year and a half. Sulfur, Mag, and Potassium. 0-0-22, extremely powerful stuff, but works wonders for my specific environment. Has worked great for me for plants under my DE lights, as well as any plants I have outdoors in the brutal desert sun. My plants happily make use of all that Mg and K, and the S is great in its own right. I use it once a month the instant flowers start setting in on plants.
 

Frank Nitty

Well-Known Member
Right. Top dress pre flower. and once about 2-3 weeks in. This depends on the plants needs and done right you don’t have to add any amendments at recycle snd never have to re-“cook” soils. At harvest just cut at base maybe take the woody pieces or root out and mix-repot- reuse. I do it all in one day if I’m pressed for time.


Not only the nutrients but any compost or ewc topped will now be incorporated into the mix. All good stuff. Sometimes just perlite if needed during recycle
Wish I could do this while using autopots
 

Three Berries

Well-Known Member
My mistake. I must have glanced over where you said "Bit of light burn but first time using LED" earlier in the thread. Definitely what's happening here, other than that, no issues and keep doing what you've been doing. Just gotta raise the lights a tad is all. You clearly know what you're doing, and what your issues are. These new lights are so intense and different, that those of us coming from Single Ended bulbs have had to learn a lot all over again.

Definite learning curves with these new lights. My DE caused similar issues and caught me by surprise.

I've noticed that I usually have to dim the DE during the last few weeks of flower, even if I have proper light distance. Plants love every last bit of light from those lights right up until around week 5-6 of flower, I've noticed. Makes sense, considering how the sun's intensity and spectrum change from summer to fall.


What is your RH? I used to run 40% with single ended bulbs, but once I switched to DE the plants always looked like shit if RH was below 50%. Especially in flower. Increasing your RH will definitely help with the light's intensity as well. So I would say the buffering has already been spent. And some good K is floating around looking for a home.


Sometimes LEDs can cause deficiencies like that on the canopy due to their intensity and spectrum. This usually happens with Mg, but it can happen with K too. Both Mg and K play a vital role in chlorophyll production, and photosynthesis by proxy.

Even though the canopy temps are likely cool enough, the intensity of them can still cause damage on the canopy. Due to the extra spectrum LED/DE bulbs bring to the table, it isn't uncommon to need to bring extra Mg and K to the table to compensate. More photosynthesis = more nutes.

Still some sexy nugs though. Regards.





Interesting. So do you just use less lime to compensate for the buffering capabilities of the potassium bicarbonate?

I've grown quite fond of Langbeinite this past year and a half. Sulfur, Mag, and Potassium. 0-0-22, extremely powerful stuff, but works wonders for my specific environment. Has worked great for me for plants under my DE lights, as well as any plants I have outdoors in the brutal desert sun. My plants happily make use of all that Mg and K, and the S is great in its own right. I use it once a month the instant flowers start setting in on plants.
I only add it to the flower nutes to pH balance. But I over flushed and got a K defic so I am added that to rainwater for a couple of days. I usually add limestone at the beginning. I only use maybe a teaspoon to a gallon, gets the 6.6 rainwater up to 7.0-7.2

So the buffering is already spent and it just some free K+ floating around.
 

Nutty sKunK

Well-Known Member
My mistake. I must have glanced over where you said "Bit of light burn but first time using LED" earlier in the thread. Definitely what's happening here, other than that, no issues and keep doing what you've been doing. Just gotta raise the lights a tad is all. You clearly know what you're doing, and what your issues are. These new lights are so intense and different, that those of us coming from Single Ended bulbs have had to learn a lot all over again.

Definite learning curves with these new lights. My DE caused similar issues and caught me by surprise.

I've noticed that I usually have to dim the DE during the last few weeks of flower, even if I have proper light distance. Plants love every last bit of light from those lights right up until around week 5-6 of flower, I've noticed. Makes sense, considering how the sun's intensity and spectrum change from summer to fall.


What is your RH? I used to run 40% with single ended bulbs, but once I switched to DE the plants always looked like shit if RH was below 50%. Especially in flower. Increasing your RH will definitely help with the light's intensity as well.


Sometimes LEDs can cause deficiencies like that on the canopy due to their intensity and spectrum. This usually happens with Mg, but it can happen with K too. Both Mg and K play a vital role in chlorophyll production, and photosynthesis by proxy.

Even though the canopy temps are likely cool enough, the intensity of them can still cause damage on the canopy. Due to the extra spectrum LED/DE bulbs bring to the table, it isn't uncommon to need to bring extra Mg and K to the table to compensate. More photosynthesis = more nutes.

Still some sexy nugs though. Regards.





Interesting. So do you just use less lime to compensate for the buffering capabilities of the potassium bicarbonate?

I've grown quite fond of Langbeinite this past year and a half. Sulfur, Mag, and Potassium. 0-0-22, extremely powerful stuff, but works wonders for my specific environment. Has worked great for me for plants under my DE lights, as well as any plants I have outdoors in the brutal desert sun. My plants happily make use of all that Mg and K, and the S is great in its own right. I use it once a month the instant flowers start setting in on plants.
Yeah I had my setup dialled in nicely with my MH but the lack of infrared of this LED is making my room too cool, leaf surface temp is only
Around 22-23c. Mainly been battling Ca issues but finding increasing it to keep it at bay is working somewhaf

Humidty is 51% just now usually around 50-55%

I’ve dimmed the light to 65% as can’t go any higher.

The buds have faired better on this plant which didn’t dry out. Was my mistake of having the plant to near the opening off the tent. Since it’s in a air pot the hot dry was drying it out faster than the others. Sorted now with a wee panel to deflect the air.

7B089A9A-4770-47E8-8D25-061930CAF279.jpegA8C2CA0D-BBEF-40A1-B096-C8D771D82BCD.jpegA72B174D-ED2E-4592-9A3B-A60707A3625B.jpeg
 

hillbill

Well-Known Member
I run small containers and go 28 days from flip or placement in flower tent. Mostly high P Guano and EWC and Black Kow, conservative on all. Weak teas about 1/3 watering with Alfalfa Meal, Kelp Meal and minerals.
 
Top