Hydroponic Experiment: Kratky Method

One of my gardening goals for 2017 is to be able to eat something I grow fresh everyday. Yes, every single day of the year. Problem#1: it's winter and nothing is growing outside. I don't have a greenhouse and don't plan on building one, so I need to figure out how grow something indoor. Problem#2: Hydroponics could work, but I don't want to invest in setting up a costly, complicated system. I want something fast, cheap, practical. Something off-grid, combat-style.   



I came across a few Youtube videos on a hydroponic method called Kratky, named after BA Kratky (University of Hawaii) who published this in 2009. The idea is simple, grow plants in static, non-circulating nutrient from beginning to end. No pump, no plug, no power. The key here is to allow the plant to have a pocket of air 'gap' between the root and the liquid. The nutrient is filled up high, and as the roots grow and reach down, the nutrient level retreats. By harvest time, there should be hardly any liquid left. 
Important to note here is that I didn't invent this. People were already doing this successfully. See below for list of learning resources. 

What you'll need: 
(I wanted to do this as cheap as possible)
1. wide-mouth jars - I use pint, but probably should find larger sizes 
2. 3-inch net cups,
3. peat pellets (Jiffy)
*note: don't use peat pellet in normal, circulating system. 
4. clay pebbles 
5. hydroponic lettuce nutrient powder (Urban Hydroponics). Other kinds would probably work fine as long as you use it according to manufacturer's instruction. 
6. lettuce seeds 
7. water 
I got item 2,4,6 from Amazon, the rest I gathered from around the house. Overall this costed me around $25 in supplies, and will probably last through numerous growing cycles.

















The steps:
I germinated lettuce seeds in hydrated Jiffy pellets like normal. I over-seeded, meaning there were too many seeds in each pellet -- way more than you'd normally do if you wanted a full-sized heads of lettuce. I wanted a bunch of smaller plants so I can continuously harvest individual leaves over a long period of time (cut and come again style). Within a few days, the seeds germinated, and I put them in as much light as my window can let in at this time of the year (late December).



Once the seedlings are about a week old, I popped the whole thing (pellet+plants) into the 3-inch net cup, and weighed it down with some pre-washed clay pebbles. *important - soak and rinse these pebbles well before use. In a separate container, I mixed the hydroponic nutrient powder with tap water and let it dissolve well. The ratio is 0.3 gram nutrient powder per 1 pint of water. 

A note about the nutrient: as Gary (The Rusted Garden) mentioned in the seed-starting video, plants don't care and won't care if the nutrient you give them is organic or not. This stuff I use is not organic. In fact, it is the opposite of organic -- synthetic nutrients made by human. However, to plants, nitrogen is nitrogen. They have no way to sense if the nitrogen came from a broken down grass clipping or synthetic nitrate. In my outdoor summer garden, I am a hardcore organic gardener. I compost, and use all organic fertilizer. I build my soil with organic matter and healthy microorganisms, letting stuff break down over the season and nourish my plants over time.  In hydroponic setup, none of that exists. Nutrients come in the form of chemical compounds that plants can readily absorb and utilize. To me, as a biologist and a gardener, as long as there's no heavy metal and it is intended to be used in hydroponics, it is safe to eat. In fact, I've already eaten a good amount of my hydroponic harvest and I'm still alive and well. 

Back to the setup, Once the plants were situated in the net cup, I dropped the whole thing into a mason jar (it should fit snuggly) and filled it with the aforementioned nutrient solution up to just covering the lower part of the Jiffy pellet, making sure the pellet stayed moist. I set this near a bright window and let it grow. 



Here's where I deviated from the book. In standard Kratky method, you're not supposed to fill the water until harvest time. However, I've noticed that my plants are using the water much, much more quickly, maybe because there's simply too many plants and the water evaporated through the space between the clay pebbles. So I decided to replenish the container with water (plain water, no nutrient). My rationale here is that this will bring the concentration of whatever nutrient is in the jar back to the original level.  

Two weeks later, I noticed that some of the leaves started to turn pale green, almost white. This is a sign of nutrient deficiency. The overly crowded plants were using the nutrients so quickly they'd run out of it. One problem here though, I had no way to tell what nutrient ran out first (i.e. think limiting reagent, my chemist friends out there). I suspect nitrogen was probably the first to go, since leafy greens are heavy nitrogen feeder. Regardless, I decided to just change out the whole thing and filled it back to the same level with the same original (but newly mixed) nutrient. The plants started to grow new green leaves again almost immediately.  

A note about root: some people wrap their jars with paper or foil, or use non-opaque containers that don't let any light through. The main reason is to inhibit growth of algae (they use the same nutrient as plants, and need light). Algae are (usually) harmless, they just look green and yucky, so people don't like to look at them.   As far as plant roots are concerned, they don't care if you expose them to light. Plant roots (most, anyway) don't perform any photosynthesis whatsoever, so exposing them to light won't do any good (or harm). I just left my jars open so I could see what was going on inside, observe the root growth and monitor the nutrient level. And, since I swap the nutrient solution and clean out the jars every few weeks, algae have no chance to grow anyway. 

I started picking the leaves to add to salad at 3 week, and am still picking now (about 4 weeks later). We'll see how long these little guys can continue to produce. 






Variables I still need to work out: 
Nutrient changing regime 
Seedling density - what's the maximum amount of food I can grow in a given space
Jar size and cost/ benefit 
Try other kinds of plants - I am experimenting with arugula and basil now
(leafy greens seem to work best with this method. For tomato, pepper, or other fruiting plants, you'll need a full-fledged hydroponic system)


Online Resources:
Beautiful lettuce by frugalgreengirl: https://youtu.be/TXLYUjEbmog
This is the setup I modeled mine after, except I use Jiffy pellets instead of rockwool

Will it Kratky: https://youtu.be/BNiQNHDaxrE

Cheap Kratky setup by Khang Starr: https://youtu.be/uqUn5N9U3IQ
Outdoor Kratky (also by Khang): https://youtu.be/LQQlHnQ7fPU

Kratky on Instructable: http://www.instructables.com/id/Kratkys-non-circulating-hydroponics/




Disclaimer: I wrote this for my own personal record and to collect my thoughts. Please feel free to read, like, comment, share as you see fit. But this is by no mean authoritative (i.e. don't sue me if you screwed up your garden).  Also, I don't work for and am not paid by anyone mentioned above. 

2016 Garden Review

A quick review of my first garden in 2016

** link to pics broken; I'll fix this soon**

Now that my garden is finally done for the year, it's time to look back at what went down...

It all started with a seed exchange event organized by Grow Pittsburgh back in late February.  The event introduced me to the gardening community in Pittsburgh. I picked up a few seeds and felt obligated to grow them.























I started seedlings indoor in late winter under fluorescent light. The hexagonal cells (Jiffy) worked really well, and soon I ran out of space under the light. I used sterile seed starting mix (also Jiffy), and normal CFL light. Nothing fancy.



I got a bit too ambitious (and too excited) and put out tomato seedlings too early. They all got killed by a late frost... so I had to start again. Nature had a way to remind us winter wasn't over yet.

Not all was lost... snow peas, strawberries, and kale survived the frost surprisingly well.


More tomato seedlings sprouting. They were later separated into individual cells.


By mid spring my front yard was filled with plants in pots and gallon buckets. Some of the pots I got for cheap from yard sales (hint: spring cleaning) and some I got for free from restaurants, thus diverting them off of landfill -- restaurants throw away perfectly good food-grade 3 and 5 gallon buckets every few days or so. All I had to do was drilling a few holes at the bottom, rinse, repeat.

For soil, I first used whatever was organic and on sale at big box store. I later learned that not all soil are created equal. I later added rich, dark compost, made locally by AgRecycle, and aged leaf mulch -- both were purchased relatively cheap from Garden Dreams.  For fertilizer, I only useed Jobe all-purpose organic fertilizer, made mostly from chicken bone and feather. What I like about this particular one is that they inoculate it with beneficial microorganism to help kick start the living soil.

Late April, I harvested my first baby kale, followed by other spring leafy greens





I visited the May Market (spring plant sale) on Phipps lawn and picked up a few more seedlings.




I joined Lawrenceville Organic Community Garden (LOCG) group and got to work with some awesome volunteers and learned a lot about city gardening. It's a small garden with a few raised bed but very productive. We had a late start, but got (mostly) everything planted by June.






My first project was planting potatoes in raised bed using the lasagna method, where 'seed' (sprouting) potatoes are planted low in a tall-ish bed (box), and more soil is added as the plants grow throughout the season. We had nice green foliage all summer, but not very much potato yield. Still not sure what the cause was, but I speculate too much nitrogen.



Strawberry setting fruit in late May. The seascape variety did best at my home garden.


Snow peas in late May. Not very good yield. I blame it on the weather... summer came in full force quick and soon it got too hot for the peas.



Early June - strawberries ripening in a hanging basket at home. Meanwhile at the community garden, we had good harvest of lettuce (plus other greens), chamomile, and more strawberries.  We also harvested garlic (planted earlier the previous fall) and hung them to dry in the shed.







I went out of town during a hot weekend in June, and a few of the bigger plants got dry and sad-looking. This is one downside of growing in containers -- poor moisture retention. However, they managed to flower and set fruits a few weeks later. Maybe the stress actually induced the flowers.. (?)



young tomatoes after a mid summer thunderstorm



A handful of my plants were 'rescued' from nursery and community garden. I hate throwing away extra seedlings. Below are two of the Japanese eggplants I rescued from LOCG.



immature eggplant


more eggplants later in the season






One of the plant I was very excited about but didn't have success with was summer squash. This photo below was taken in June, when the fruit was small. It never got any bigger and the plant eventually died from some sort of fungal infection, possibly powdery mildew.



Speaking of pest, I had some major aphid problem earlier in the spring. The little green bugs infested some of the young tomato and herb leaves and sucked the life out of them.. They didn't kill the plant though.  After attending a workshop at Garden Dreams (i.e. best plant nursery ever!) I found that nature was already taking care of this by itself. I found a few of the aphids being 'mummified' by parasitic wasp, a predatory insect that lay eggs on the aphids; and the larvae, when hatched, eat the pest from the inside out, leaving behind some gross-looking carcasses.  Below is a closeup shot of the dead aphids taken with my new macro iphone lenses. I haven't had any more aphid problem since then.



Late June - some of the tomatoes were getting big. First the black cherry, followed by cherokee purple -- both are heirloom.





ripe cherokee purple -- very pretty color and unique, full flavor.



Meanwhile at LOCG: staking tomatoes and harvesting berries.




Early July - pepper are in full production. Shishito plant, my favorite Japanese heirloom, is loaded with fruits, which are good in stir fry or pan seared with sea salt.




Aurora, an ornamental pepper, looks pretty but the fruits are very hot. They start out purple, then turn pale, yellow, orange, and red as they ripen. The plant stayed very small but quite productive. I actually kept it over winter this year hoping to get a head start next spring.

cross section of aurora peppers. Notice the mature (top) and immature (bottom) seeds


Late July - harvesting my first black cherry tomatoes from the 5-gallon buckets. This is my favorite cherry tomato this year. The plants are the first to produce and last to die (due to frost), and the fruits tasted great.





Early August - a few other varieties are ripening.

Green zebra tomatoes. These are medium-sized with cool stripy patterns. They're considered 'new' heirloom, developed within the last few decades, open pollinated. The fruits turn from light green to yellow, while the stripes stay dark brown. The flavor is great too -- tangy and refreshing.




Sprite tomatoes -- The only grape type I grew this year. I wasn't planning on it, but 'rescued' the plant from a nursery. The plant had a shaky start, but managed to produce a moderate crop. Taste-wise, it was meh...



Habanada -- This is a fun variety, another 'new' heirloom developed through a process called marker-assisted breeding (fascinating stuff) at Cornell University. It looks and tasted exactly like habanero, except with zero heat. Yes, absolutely zero. You can actually make sherbet out of this. Typical habanero is at around 300,000 scoville. I can think of a fun drinking game akin to Russin roulette where you have five habanadas and one habanero...



Hinkelhatz: I grew this mainly because it is a Pennsylvania heirloom cultivated by the dutch. The fruits are moderately hot and fleshy. It was advertised as cold-tolerant, but in my garden, it was the first to go when first frost hit.


Shishito (see above)



Aurora (see above)




Late August was peak production for all my peppers. Below are all of them this year:



As companion plants, I also grew some basil, shiso, and other herbs like mint and sage. Tomatoes and basils make great company both in the garden and on the dish.




eggplant, cherokee purple tomatoes, shishito pepper, and Hinkelhatz pepper

I had some problems with blossom end rot, especially with bigger tomatoes (purple cherokee in this case). This is a calcium deficiency issue due to the lack of calcium in the soil or a calcium transport problem. I was almost certain there was enough calcium in the soil (rich compost + crushed eggshells) so it was probably the latter -- inconsistent watering can impair calcium uptake and transport.  This was exacerbated by the plants being grown in crowded containers in hot, dry summer.  

At LOCG, I got to see people work with other fruits and veggies that are more challenging than at my home garden, or stuff I don't have time and space for, like figs and flowers.






 I attended a tomato tasting at Garden Dreams at the end of summer. It was awesome to celebrate the end of season with other gardeners in the neighborhood and the people who work there. Also nice to taste other varieties and build a wish list for next season.




Late summer harvest -- a little bit of everything.


The weather started to cool down and I was surprised to get a second crop of strawberries in September.



Not much happening in October... pepper and tomato production tapering off.



Early November, I re-potted some pepper plants (shishito and aurora) to keep indoor during the winter (more on winter gardening later).




We planted a small amount of fall crop at LOCG.
Mid-November - radishes were harvested through first frost.



Right before hard frost, I picked all the tomatoes and let them ripen indoor. They won't taste nearly as good, but this is a better use of green tomatoes than throwing them in the compost.


My second attempt at snow peas. The plants survived frost and light snow well, but we had a deep, hard freeze in mid December that killed everything.



My container garden covered by snow. This was the end of 2016 garden.




Green tomatoes finally ripening indoor in December



Overall 2016 garden was a success. It was my first year, and I learned a ton, mostly from talking to people and online.

My main sources of information and supplies:
The Rusted Garden -- Gary is very knowledgeable. He also maintains a very active discussion group on facebook.
MI Gardener -- great selection of seeds and information
Curtis Stone Profitable Urban Farming -- urban farm in Canada. I may do this one day...
Growing Your Greens -- this guy is a hardcore desert gardener
Garden Dreams -- best seedlings, compost, and friendly, helpful people
Grow Pittsburgh -- everything you need to start a garden in Pittsburgh

Last, I also want to thank the people at Garden Dreams, Grow Pittsburgh, LOCG, and my neighbors for all the help, information, and moral support.


Disclaimer: I wrote this for my own personal record and to collect my thoughts. Please feel free to read, like, comment, share as you see fit. But this is by no mean authoritative (i.e. don't sue me if you screwed up your garden).  Also, I don't work for and am not paid by anyone mentioned above.