Hydroponic Fertilizer : What I Use & How to Mix It
I get a lot of questions about the fertilizer that I am using in my hydroponic setups for growing lettuce and tomatoes. This is a thorough explanation of exactly what I am using. But keep this…
25 Responses to Hydroponic Fertilizer : What I Use & How to Mix It
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Joseph Larsen
+dymondwillow2 (I had a mess up with my math. It’s actually 9.75% 🙂 by
bad). But here’s how I arrived at my answer. Basically a fertilizer that
says 4-18-38 is basically 4% N, 18% P, and 38% K. So 100 pounds of that
fertilizer would have 4 pounds of Nitrogen in it, etc. A fertilizer that
is 15.5-0-0 in 100 pounds would have 15.5 pounds of Nitrogen. So if you
combined 100 pounds of fertlizer 1 with 100 pounds of fertlizer 2 you’d
have 200 pounds of ferltizer which would have 19.5 total nitrogen…
Dymond’s comment: 4=15=19 NOT 9%…(no backyard gardener buys 100 pounds of
fertilizer!)
dymondwillow2
April 16, 2015 at 4:03 am
Do you use the same ratio of nutrients for peppers and cucumbers that you
use for the tomatoes? And do you use the 20-18-38 for the entire growing
period?
Jerry Hendrix
April 16, 2015 at 4:29 am
If they would’ve told me this is what chemistry was used for in high
school, i would have tried a little harder
Anthony Perez
April 16, 2015 at 4:39 am
Technically your white board is wrong when you are combining your
fertilizers, it’s not really 19.5-18-38. When calculating the percentages
you need to take a weighted average of each fertilizer into account. A
formula for this is(W1N1+w2N2)/W1+W2… W1 being weight of fertilizer 1, N1
being % Nitrogen in fertilizer 1, W2 is weight of fertilizer 2, N2 is %
Nitrogen in fertilizer 2. This formula works for all nutrients just make N
into what ever nutrient in question. Also you should use all the
fertilizers mixed (ie 3 different fertilizers would be
(w1N1+W2N2+W3N3)/W1+W2+W3) regardless if it has the nutrient in question or
not. So yours (tomato and lettuce) is actually 7.8-7.2-15.2, that happens
to be the same ratio as your 19.5-18-38 but it’s in actual terms (as if you
were to mix the dry ingredients together in your 12g 12g 6g or 10g 10g 5g).
God forbid anyone from doing that, it’s not a good choice, they should be
mixed in water. Note if you used a different weight ratio of your three
fertilizers (2g:2g:1g) it would result in a N-P-K that would never be in a
19.5-18-38 ratio like the 7.8-7.2-15.2 was. Sorry for the long reply on a
fairly minor thing
Robert Duggan
April 16, 2015 at 5:03 am
hmm I can’t seem ti find any directions for the mix ratio at all on ether
website
ChrisD4335
April 16, 2015 at 5:17 am
+mhpgardener Hi Sir, I was wondering if you use the same amount
20-18-38 during the entire cycle of the suckers to the end process(
tomato)? And thank you for the recipe.
55nublet
April 16, 2015 at 5:46 am
A few months ago I was looking on Amazon at Peters 20-20-20 and it has the
micro-nutrients much like the (pink) MG Tomato formula. Just wanted to pass
that on to your viewers.
heavymechanic2
April 16, 2015 at 6:28 am
just looking into various hydroponic methods, and trying to gather as much
information before I jump in. question: will this mix work for any method
of hydroponics, or is this formula for a specific method? I am looking at
several methods: dutch buckets, NFT rails, DWC tubs, floating rafts, and
Kratky method. which all of these methods do you think this formula would
work with?
pHeQEkAp3etr
April 16, 2015 at 7:22 am
What kind of fertilizer would you use for strawberries in a raised bed?
Cody B
April 16, 2015 at 7:28 am
The best information in detail so far I have come across about the proper
fertilizer for hydroponics systems. Along with the comments below it gives
you all you need to start.
thallium200
April 16, 2015 at 7:30 am
I see through amazon that Urban-Hydroponic hasa 20-18-38 mix. I know it’s
been a couple years since this video so maybe they have introduced this
product since then.
http://www.amazon.com/Hydroponic-Tomato-Fertilizer-20-18-38-Lb/dp/B00CKCQJKQ/ref=sr_1_2?ie=UTF8&qid=1425568284&sr=8-2&keywords=masterblend+fertilizer
I was wondering if this would have the trace minerals that you had
mentioned. It reads it contains all essential micro nutrients, so I wasn’t
sure.
James Petry
April 16, 2015 at 8:22 am
Your amazing! If it wasn’t for all your videos I would be at a loss with
all the scattered ones that don’t get to the detailed point for beginners!
saymyname
April 16, 2015 at 8:25 am
Hi there
I like what your teaching, How to get the Nitrogen up,
But 4 % is not 4% nitrogen IT IS ABOUT 12 P.P.M of NITROGEN .Also your not
explant what the proper % of Nitrogen is needed in the system for Optimum
Grow
eddie vasquez
April 16, 2015 at 9:00 am
Hello! How are u? Thanks for the wonderful videos. I love them… I have
learned so much and am so greatful to you… Can’t wait for new ones this
season… If you have time, I have a couple of questions. What’s the ppm
supposed to read at? I wasnt sure if you mentioned it and I tried scrolling
through to see if you mention it in the comments but I couldnt find it…
Do I need to check the ppms or is it ok if I dont? :)
nerualrose
April 16, 2015 at 9:40 am
I have ordered the formula from one of the mentioned site but boy they do
take their time to ship. Any other name brand that are kind of available if
there is NO hydroponics store around?
Zanet Swartz
April 16, 2015 at 10:30 am
How far apart do you put your Dutch buckets for tomato plants thanks
Mike Knop
April 16, 2015 at 11:26 am
Is there any recommended test equipment for checking TDS and ph etc? A
reliable pen style that doesn’t require too much maintenance would be
perfect :)
David Troesch
April 16, 2015 at 11:40 am
How much cal nitrate do you add to the 4-18-38 nutrient? Does it have the
micronutrients already in it? Do you use different nutrient for lettuce?
Like the 10-8-22? Do you recommend it? Thanks! I hope to see you doing more
videos again. I miss you! You’ve been SUCH a help for me!
Garden4Flavor
April 16, 2015 at 12:32 pm
Hi Bobby , I would like to ask you what you think about using Pro Mix
with Hobby Formula 10-8-22 and a 1/4 ts. of Episom Salts ? Thxs
Ron Mocci
April 16, 2015 at 1:00 pm
Dear Mhpgardener
are these 5 gallons the hydroponic water or they will be additives , and if
additive what is the ratio to the hydroponic system water????
Ghurmallah Alzahrani
April 16, 2015 at 1:14 pm
most closer i have reach till 20-20-40 , bought from local fertilizer
store. is that okay for my tomato plants (planted in coco peat)
Kunal Mulik
April 16, 2015 at 1:57 pm
If your a like me, your always in a hurry. I tried to use the Morgan and
found that they move extremely slow. So I went to Amazon, and with a prime
acct., a lbs. of master blend and a lbs. of calcium nitrate (delivered
next day) cost me less than $30.
Brandon S
April 16, 2015 at 1:58 pm
hi mhp, wat is the nutrient solution for pepper plants in every 5
gallons… pls answer me plss,,,
christoff burnnhan
April 16, 2015 at 2:58 pm
You are the best teacher i have ever seen . Thanks for your amazing
detailed video and information.
adamtombar
April 16, 2015 at 3:34 pm
You are a fantastic teacher and please keep up the great work! You’re very
inspiring to those of us getting started in these areas, and thank you very
much!
scott lewis
April 16, 2015 at 3:39 pm