Fertilizer Approaches for Growing Hydroponic Lettuce
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- เผยแพร่เมื่อ 22 เม.ย. 2022
- Approaches to applying fertilizer to non-circulating hydroponic lettuce are discussed. The goal is optimum lettuce growth with maximum fertilizer efficiency. This video shows how to calculate fertilizer rates of complete hydroponic fertilizers which have a track record of growing hydroponic lettuce.
Here is a link to a University of Hawaii-CTAHR article on non-circulating hydroponic methods - www.ctahr.hawaii.edu/oc/freep...
"Corrections:" 9:06 15.5% N instead of 0.155% N; 9:17 Delete the statement "If 88.6 g N are dissolved in 3785 ml". - วิทยาศาสตร์และเทคโนโลยี
Aloha professor! I just wanted to thank you for all your research and sharing it with the world. This will give us fresh greens during our cold winter months. Greetings from Stockholm Sweden.
Thank prof, this is, by far, the best video that I have seen explaining the ratio of nutrients needed for hydroponics. It helped me a lot in preparing my stock solution for my indoor hydroponics.
Thank you so much Dr Kratky. Your videos are truly inspiring and I cannot wait to have this level of success in hydroponics :)
Ah, the professor in his element! Enjoyed the math and agricultural class today. Very interesting approach and calculations, I appreciate your detail.
Thanks, Matt for the positive feedback. I was concerned that maybe this approach was a bit too rigorous, but am happy to see your comments.
So glad I found your channel your growing technic has changed my life ❤❤
I’m so glad you are proficient in math skills! I’m not, if I ever was, but I can follow directions. Thank you so much!
I found you through MHPGARDENER a few years ago. I really need to try this both indoors and outside...zone 5 is a tough one.
Thanks for all you do and have shared over the years.
Aloha. Thank you, I just started with my first 3 test buckets. So excited. Would love info like this for other foods, that was fascinating and so informative. Thank you from Australia 🇦🇺🥰
Good luck on your project! By the way, I successfully used this growing method while on sabbatical leave at UQ-Gatton in 2000, so I know you are going to be successful.
Yay! Great videos as usual. Thank you for the review.
I appreciate your work and information in this video. This helped me immensely! After seeing probably a hundred videos on the Kratky method, I feel like I finally met the man behind the legend!
Thank you and Happy Hydroponic Gardening!
Thank you Dr
You answered my exact question
Nice to see a new video.
Thank you.
You know I like seeing the math! I'm a fan of stock solutions, I learned this from you and I appreciate you teaching this. Based on my observations in my growing environment and not on math, it seems that 80% of the Calcium Nitrate produces better results for most of what I grow... the downside is, I have an excessive reserve of Calcium Nitrate. Big thumbs up for you, kind sir. It is always good to see you and hear what you have to say.
Good to hear from you! The math gives a starting point for an optimum fertilizer rate, but you are correct in that actual observations and growing results in your specific conditions actually provide the most accurate estimate of the optimum fertilizer rate.
Thank you for your wisdom!!
Thank you very much, very helpful.
Thanks for the great video. It's changed my approach to how I measure out the nutrients. I have hard water coming out of the tap. Can you do a video on water quality? Would you dilute the hard water with RO water to bring the EC down? What EC level would you target for just the water? Or would you target the EC after adding the nutrients? So I would still use 2.05 grams of Masterblend but diluted in a greater volume of water to achieve 1.5 EC?
In Hilo, our water was not hard and usually had an EC of below 0.1 mS. I don't have much experience with hard water, but your approach to dilute it with rainwater or RO water sounds good. Maybe, use 0.2 mS as a target. The EC after adding nutrients depends on the water EC, the amount of nutrients added and the quantity of water. The approach in this video calls for adding 2.05 g of Masterblend etc. to a gal of water and adding more water if the plants need it, regardless of EC. Another approach, not discussed in this video, calls for using however much solution the plants need - all at an EC of 1.5 mS, but that usually ends up requiring more fertilizer than the 2.05 mg etc. that the plants actually need.
@@growkratky5558 Thanks! That 0.2 mS sounds like a good target. I can get that by using 20% tap mixed with RO. Once I add the nutrients I get an EC that's in the target range.
9:18 another typo. There are 88.6 g N in 2 containers BOTH holding 3785 ml for a total of 88.6g N in 7570ml. NOT 88.6g N in 3785ml. This would result in an actual 0.0234g N per 1ml of each part, 2ml total. Otherwise, an immense thanks for making this video. I've learned a lot from it.
Excellent observation - You are correct! I should just strike out the statement "If 88.6 g N are dissolved in 3785 ml".
Hi Dr. Kratky, I grew some tomatoes that grew very well but were a little sour than usual, what do you theorize the problem was? And my green bell peppers have some yellow soft spots as well.
Oh my gosh, you are the best! Thank you for going through all of these calculations with us! Would you be willing to share your thoughts on how much Calcium we should add to the growing solution for tomatoes? I’ve heard calcium deficiency causes blossom end rot, or something along those lines.
Find a complete hydroponic fertilizer formula that has a past history of growing good crops of tomatoes. Then, base your calculations on the optimum rates for any one element (such as nitrogen) and an acceptable rate of calcium or any of the other elements automatically comes along for the ride.
Hi Dr. Kratky
@9:10 of the video
There is a mistake in the percentage of Nitrogen in the Calcium Nitrate. Same should be 15.5% instead of 0.155%
Hi Kevin, Thanks for catching the error! I made a notation in the description and will update it with a correction card if I can figure out how to do it.
Dear dr, hello
Can compost tea be used?
Hi Dr. Kratky
I have calculated the N value in the solution you are using and it happens to be about 105 mg/L. Isn't that too low for lettuce. Correct me if I am wrong but moat lettuce requires about 150 mg/L of N to produce a satisfactory head of about 175-250grams.
There are many commercial farms that runs N at180-200 mg/L.
This was great. Thanks a lot.
What temperatures and humidity in your greenhouse?
In Hawaii, we grew lettuce from sea level to 4000 ft elevation where the outside day/night temperatures usually ranged from 85/65 to 70/45 and which became 10 degrees or more warmer in a greenhouse. Relative humidity usually ranged from about 50 to 100%
If the jug of stock solution is prepared one week in advance, is any shaking necessary?
Good question, Jeb. Yes, absolutely shake or stir the stock solutions before using.
i think blocking all the sunlight with aluminum foil helps to keap root rot away .keeps the algees away to .
thank you for all the insperaton you give me .
Love the videos Dr.Kratky! Are you aware of anyone currently doing any experiments using chicken manure as hydroponic fertilizer? I've only managed to spot one paper on it and wondered if the increase in traditional fertilizer prices might drive interest in coop poo
No, I am not aware, but hope more folks experiment with organic fertilizer sources as there is a demand for such information.
Thank you for a very informative video and the Kratky method! What would be an approximate ratio of nutrition needed for lettuce growth vs vegetative grow state of cannabis or tomato(Since that's what most complete hydroponic mixes seem to aim for). Also my solution is missing the sulfur component. Is that something that i should supplement? How do you feel about Silicone additives?
th-cam.com/video/zTWBvQboSFY/w-d-xo.html at about the 9 minute mark discusses my approach to tomatoes. Yes, sulfur is needed. Read a silicon review paper by Epstein to formulate your opinion whether supplemental amounts are needed.
What is suggested for EC value?
Aloha Dr. Kratky!! I’m new to your hydroponic method. I’ve started around 5 months ago to try and grow mostly leafy greens. I have them in black totes 12 gal & 7 gal. I’ve noticed that my manoa lettuces and head cabbages have been getting younger leaf tip burn and older whole leaf turning brown with spots. I have them under grow lights also. I’ve done a few changes to the amount of fertilizer (more or less). But still the same. Might be the lights? Too close or on too long? I have them on timers for about 12 hrs. I have them about 2 feet from the plants height. Love your work by the way. I’m in HPP (keaau) area also. Not sure if the climate might be the issue also. Thanks so much🙏🏼🤙🏼🤙🏼🤙🏼
Manoa lettuce typically gets tipburn during the warmer months -particularly at lower elevations in Hawaii. Symptoms should lessen during the cooler weather. Also, you may notice that cabbage is normally grown at higher elevations like Volcano, Kamuela and Kula, because it prefers cooler weather. You should have better results with a leafy lettuce variety in your location
@@growkratky5558 thank you so much for your info. Love your work and absolutely appreciate your input. My hunch was correct. I figured it was more to do with climate rather than nutrients. It is warm here and very humid. I’ve grown one successful crop of cabbage once in containers with soil. And when I think back, it was cool for a good month and a half. Best cabbages I’ve ever grown.
Hello Professor, what is the EC I should start with for Lettuce in the Kratky method?
1.5 mS. If your weather is hot and dry, then use a lower EC of about 1.0 to 1.2 mS.
how about micro nutrients needed?
How many times should i add nutrient mixer to growing solution from seed to fully grown lettuce?
Only one fertilizer application is needed prior to planting - provided that you have a tank with at least 2 quarts of water per plant.
If I want to pick individual lettuce leaves rather than the entire plant for a longer harvest, would I need to continue to add nutrients to any extra water that I add?
It should not be necessary during the first few weeks of harvesting, but if you harvest for a long time, then adding nutrients would be beneficial.
Hi Dr Kratky! I'm curious if the dry nitrogen weights and ratio of other plants are available somewhere?
Can the same technique be used to flowering/fruiting species by weighing fruits? Or is this already available somewhere in the internets?
Thank you! Why your channel is not the #1 result when searching kratky is beyond me.
Knott's Handbook for Vegetable Growers (Maynard and Hochmuth) likely has some of the information you are looking for. Thanks for you kind words.
@@growkratky5558 oh. Thank you doctor! I will check that out.
There are tons of videos on your method. Could you make more simple ones, pls 🙏🏻
Thanks for the insight. I have some ideas to simplify the process and if they work, then I will make a youtube.
What do you mean by "the fertilizer nutrients are either in the *lettuce* or in the nutrients solution"? Is there a way to have plants with their "own" nutrients without them in the water???
This is as compared to growing in a soil system which usually ties up some nutrients and leaches some nutrients during watering
@@growkratky5558 Ah okay, thanks :)
Dear Dr. is this formula for master blend work with all green plants Thanks
Actually, this is a tomato formula, but it works for other plants as well. If you grow only one crop, seek out a formula specialized for that crop. However, if you grow a variety of crops, usually a tomato or lettuce formula will work pretty well, although not quite at the optimum that a specialized formula might work for a specific crop.
Aloha dr kratky. What ec and ph should i start with the lettuce ?
Shoot for an EC of 1.5mS ( a little lower if you have hot weather and a little higher if cool weather) and a pH in the range of 5.5 to 7.
Aloha Dr Kratky. How low can I go on my EC since thw weather in Philippines is hot
Anyone here trying this in the Caribbean.
Any advise to deal with heat
Try using shades
so if growing 8 lettuces in 5 gallons of water i need 685mls of A and 685mls of B?
At 10:06 I am suggesting that you add 137 ml Stock A + 137 ml Stock B per 8 plants. It would be the same whether you use 5 or 10 gallons of water.
@@growkratky5558 ah excellent thankyou so much
Hi Bernard~ Aloha~ Its your friend Tor in Portland. I sent a correspondence to you, but the old academic email bounced back my email. If you are bored and want to see the short video I made for you... bomb me a good email. I see you are well from your continued video posts! Much love~ Tor