Some of my Most Useful Bookmarked Web Resources

These are Internet resources I found particularly interesting. Now, there are many, many more good and useful web site. These are just some that I think fill some gaps in common knowledge and provide some things that might be more difficult to find just by searching, even if someone knows what to search for. I begin this list with my version of July 2022. I will likely add to it from time to time without making a separate blog entry, so if you care, you can check back from time to time. So, here goes, in not particular order. Click on any to get the link.

 

https://kratky.weebly.com/

An excellent place to learn about Kratke method Maintained by a friend of Dr. Kratky.

 

Grow Kratky - YouTube

Dr. Kratky’s YouTube channel. Mainly a collection of tips and projects. Not really an education in the method. Get that from the earlier site. But, hey, this is The Man. He’s retired.

 

https://pulsegrow.com/

Pulse web site. They sell VPD devices, but the site has about all you could want to know about VPD and edema, with charts.

 

Getting to the root of lettuce tip burn - Greenhouse Canada

Good short article on lettuce tip burn.

 

How Many Bubbles is Too Much for My DWC? – Hydroponics Space

Useful slant on a very common question.

 

Why most of the time a “deficiency” in hydroponics is not solved by just “adding more of it” – Science in Hydroponics

Another good slant on a common issue.

 

Calcium’s behavior in hydroponics – Science in Hydroponics

Along the same lines, focused on Calcium.

 

Hoocho - YouTube

Hoocho’s web site. If you don’t know Hoocho, now’s the time. A very prolific developer of ideas that you can’t afford not to know.

 

Farmer Tyler - YouTube

Definitely go here and watch the video instructionals on Plants and Light.

 

Comparing the conductivity of two different solutions – Science in Hydroponics

Think you know all about E.C.? 

 

Hydroponic Nutrient Availability : What “Pushing Out an Element” Really Means – Science in Hydroponics

Think you know about lock-out and deficiencies?

 

A one-part hydroponic nutrient formulation for very hard water – Science in Hydroponics

If you have extremely hard water, you may have to learn a lot more, but this will get you started.

 

Apogee Instruments Inc. - YouTube

The straight stuff on light for plants. Dr. Bruce Bugbee.

 

What is an ORP meter and why is it useful in hydroponics? – Science in Hydroponics

Just what it says. If you don’t know the term, read this.

 

Host and resident bacteria join forces to control fungi in plant roots

Just one way those good guy microbes work for you.

 

Spring Hill Farms - YouTube

Went out of business upon the very sad death of one of the principles, but the YouTube channel still has many good pieces, particularly on microgreens.

 

Growing Hydroponic Carrots - A Full Guide | Gardening Tips

One of the most difficult of hydro crops. I don’t know if you can pull it off, but it you want to try, you have to read this.

 

Hydroponic Onions – The Secrets To Getting Giant Onion Bulbs – Hydroponics Space

Another tough crop. You’ll need to know all you can know to try it.

 

Larry & Eyvonne Hall - YouTube

Not 100% hydro, but these are some growing fools with a ton of videos on all sorts of useful topics.

 

New Revision of my Book Posted to Smashwords

I don't think I've mentioned it before on this blog, but I have a book out on hydroponics, and I have just posted the July 2022 revision and expansion on Smashwords. The title is Start Here for Hydroponics, and that's pretty much the intent. 

If you have a download of my book already, you can go back to Smashwords and download the new revised version, which adds some topics (some from this blog), makes some corrections, and increases the size to 186 pages.

If you do or don't have it, it is free to download, Just choose the pay nothing option at Smashwords. I didn't write it to make money, and neither this blog nor the book is not in any way monetized. I chose Smashwords because they will let me give the book away, which Amazon will not allow. If you choose to pay nothing, I can guarantee it will be worth every penny you pay for it.

If you don't already have a copy, I intended it mostly for beginners. It covers theory and methods, and rather than try to provide pat answers to problems, I try to prepare you to find your way through them, eliminating possible issues one at a time. Too often, pat answers, like declaring a nutrient deficiency from a photo of a leaf, are just wrong. I don't expect universal agreement. I never argue on the Internet for the classic reason involving pigs and mud wrestling. I don't worry when people disagree with something I say. I'm not an authority. Fact check me as you would anyone else. Just because I wrote a book doesn't make me any smarter than anyone else.

I describe most popular methods and basic construction for some methods, but for most, you can go onto the Internet for construction details. I don't know everything. I don't know that anyone does.One thing I don't do is pretend to present a set of instructions that guarantee success. Too much content on the Internet is by people interested mainly in Likes and Subscriptions. And they have found that if they pretend that some plan they put up is easy and has no problems, many people will Like it without trying it. I've seen described projects that are doomed to fail and many that happened to fail to mention the problems that will arise. That's part of why I dislike pat answers from some anonymous poster who happens to have found a web site and want to pretend to  knowledge.

The book is roughly divided into two parts, one with essentials and the latter parts that go deeper and feature some focused articles. A lot of it was driven by questions and answers on the subReddits Hydroponics and Hydro. Like all such things, it is just a resource, and it is up to you to think your way through things. But the more you know, the more you grow.

https://www.smashwords.com/books/view/1112004

A “Mini-Bucket” Line System Suggested by a Reddit User

A while back, on the Hydroponics Reddit, the user GrnMtnTrees presented an idea that I thought had merit, and it demonstrates the principle that it doesn’t matter what you call a method, if it provides for all the plant needs. His idea was to begin with something that looks much like RDWC or NFT in a pipe. But instead of flowing nutrient through the pipe for the roots, he proposed dripping it into the top. This immediately brought to mind a Dutch bucket line, AKA Bato bucket.  

If you’re a visual sort of thinker, you can almost imagine a line of Dutch buckets morphing into a line of very small Dutch buckets and then the small buckets growing together. The result is a method in which the pipe becomes the body of many buckets and serves the function of the return manifold in the Dutch bucket line. A Conventional Dutch Bucket (Single Bucket Only Shown)

The Mini-Bucket Line

The theory of operation is very like Dutch bucket. At each plant position, the plant is supported in a net cup by a medium like LECA. Nutrient is provided by drip lines embedded, as usual, far enough to apply the nutrient to the crown of the root, so the LECA at the surface doesn’t stay wet and liable to grow algae. From there, it’s just Dutch bucket all the way. 

Nutrient drizzles down the root network in thin, randomly changing streams. The roots, as in Dutch bucket, take atmospheric air through those thin streams. Rather than the individual bucket drains of a Dutch bucket line, nutrient in this line collects in the pipe and is led back to the reservoir. Even the safety net of the Dutch bucket is provided. If the drain end of the pipe if through a riser of bulkhead connector mounted so as to keep a small depth of nutrient in the pipe at all times, the plants can survive a pump failure for a reasonable time. Small low, dams in the pipe could do the same thing. 

This “mini-bucket” line fills a niche in the Dutch bucket family. Dutch buckets are not particularly efficient ways to grow small plants, like herbs and greens. Too much bucket and not enough plant. But in the mini-bucket line, it’s as efficient as any channel system for small plants. And it has no really critical design or operating parameters. So long as the drip flow is not a solid gush of nutrient through which the roots could not get air easily, anything from a drip to a drizzle will work. 2” cups in 4” pipe should allow for a small plant’s roots to form a loose network and take nutrient from many tiny streams. 

It also is large enough pipe to not have roots immediately grow to clog it, although as with any channel system, you have to check periodically for that. At least it cannot grow roots into the small siphon in a Dutch bucket to clog the drain. If constructed of tiers of pipe arranged as a wall or slope, each pipe at a different height, it shares the usual consideration of achieving some reasonable balance of flows more or less equal at all tiers. This can be done using valves to gate back the higher tiers or by pumping to a manifold above the top tiers and feeding plant positions down from there. Best to test before loading with filled net cups, so you can see the flows. But some variations among flows at different levels should make little difference. 

With any sort of drizzle, roots will feed efficiently. Restraining the flow to allow roots to take air through it is more critical. As always, reservoir size is chosen according to how many plants it serves and how often you are willing to refresh the nutrient. As with all Dutch bucket lines, circulation runs continuously, and no air pumps is used. 

An alternative way to operate a conventional Dutch bucket is to fill the bucket with coarse medium, usually chunky Perlite. Roots grow within the Perlite, and nutrient drizzles down through it all. While in theory that could be done with the Mini-Bucket Line, changing plants would be tedious at best. The Mini-Bucket Line offers an alternative for those who want a channelized system, either arrayed vertically or horizontally. It can take its place alongside RDWC in pipe and NFT. It offers non-critical design, easy operation, and plant safety in the event of a pump failure. And there is essentially no size limit. Nutrient does not flow through many root masses, becoming progressively exhausted. So long as the proper drip flow can be had, all plant positions get fresh nutrient. And unlike RDWC, there is no need for mechanical aeration, making it a silent system.

An Outdoor, Nearly Rainproof, Kratky Tote System with Low Maintenance

 

Kratky is a good method for outdoor growing. Because it needs no power, it can be positioned anywhere where it gets sufficient light. Vining squash and melons can trail out on a patio, rather than in the grass. One problem of growing in outdoor containers is heavy rain diluting nutrient. I began growing tomatoes and peppers in Sterlite 40-gallon totes, one or two plants to the tote. But the lids of these and many totes are recessed. Most of the area of the lid is below the raised rim, so the whole lid becomes a rain catchment, and if net cups are just set in 2” holes in the lid, the rain drains into the nutrient.

 

To prevent that, I designed these with risers that support the net cups above the lid’s rainwater level. I use 2-3/8” grommets. The interior of those grommets fit the outer diameter of 2” Schedule 40 PVC pipe. A short stub of pipe fits snuggly in the grommet.

Most of this report will deal with construction problems, because there are some that I had to deal with, but hopefully, you can avoid most of them.

First, the grommets specify a 2-7/8” drilled home. That is a hole drill size not commonly found in the inexpensive hole saw sets. I bought one on Amazon with mandrel for $14. But the groove around the grommet that grips the wall it passes through is fairly deep, and I found that I could make a 3” hole that would seal just as well, and all common inexpensive hole drill sets have that size, and such a set is very useful and indeed necessary for DIY hydroponics.

 

 

In the grommets I had, that groove is very narrow, 1/16”. The lids of most totes are significantly thicker than that, and it would be difficult to fit the grommet. I found that if I used a rotary tool to bevel the edge of the hole, it helped me get the groove to start slipping over the edge of the hole. Once I was doing that, construction was much easier. Trying to fit the grommets without making that modifications was incredibly frustrating.

I have since found that the grommets are also available with a 1/8” groove, which is likely to fit far more easily. They are more expensive. $5 apiece, rather than $3. Both are on Amazon.

Grommets in the 1/8” groove version.

 

I also learned to use the tool to bevel the outer edge of one end of the short piece of pipe so it could more easily begin to slip through the grommet. Totes got three risers installed. My initial intent was to use the two outer ones for plants and the one near the middle front as an inspection and service port. But I went ahead and used all three for plants on some totes.

It only takes about 2” of pipe for enough to extend above the rain line. I happened to have some 2” black PVC tube, which is why my pipe stubs are not white.

This obviously limits to 2” net dups. But I use 2” net cups for everything and find no problems with larger plants like peppers and tomatoes. So, the Kratky tote’s only rain exposure is the very minor one of what rain could make it through the foliage to run through the medium in the net cups. Rain falling anywhere else will simply accumulate in the recessed lid, prevented from getting inside by the grommets and risers, and can be easily dumped by tilting the lid to prevent mosquito breeding.

Note that the risers will prevent a new seedling that has not had roots descend from reaching the nutrient at first. One way to address this is to insert a cloth wick into the net cup. You can also slide the riser down into the grommet so that the net cup medium can reach nutrient in a full tote.

Instead, I grow my seedlings in a Kratky bucket with several holes in the lid until they send down sufficient roots. That also provides them some indoor protection from wind and sun. When they have sufficient roots, I lead the roots down through the risers. The nutrient starts high enough for them and is allowed to drop to one-third in the usual Kratky way. 

 

This is a finished tote.

 

 

Underside of the tote lid.

Newly started tomatoes.

 

 

The riser idea can be used with any plastic container that has the recessed lid problem of catching rain. Also, even though it has wheels, do not hope to move the tote after is has been filled. It will weight well over 200 pounds and will not budge.

A Compact Shelf Size No-Leak Ebb & Flow System

I like ebb and flow systems, but I wish they were more compact. So I set out to design an ebb and flow system that would fit comfortably on a shelf. I began with two Sterlite 10-gallon totes. Each is 25-3/4” x 18-3/8” x 7-1/8”. I determined to stack them and use the  bottom as the reservoir and the top, filled with LECA, for growing. I wanted them easy to take apart and clean and essentially free from leaks. 

 

The theory of operation in this type of ebb and flow is that the timer turns on a small pump that fills the growing tray through a connector that has a grill protecting it from clay pebbles dropping in. An adjustable riser is set to the desired nutrient depth. Nutrient is pumped up and continuously overflows through the riser and returns to the reservoir. At the end of the timed flood period, the pump stops, and most of the nutrient drains back passively through the pump. A small quantity of nutrient remains, but that is on no consequence. It may actually protect the roots in the event of a pump failure that is not discovered promptly.

In the lid of the lower tote, the reservoir, I made a 2-inch hole in the lid near one end. 

This would be to inspect and service nutrient. The top, then, could sit back far enough to clear this port. I leveled it using 1” Styrofoam.

In the growing tray, I mounted a set of common ebb and flow fixtures, a riser to set depth and a fill and drain connection. These pass through the bottom of the tank. The pump was connected directly to the drain and fill connector with ½” vinyl tubing which fit both the connector and the pump discharge. When held aloft, the pump hangs below the growing tray.

First, I drilled the holes for the ebb & flow kit. 

Then I set the growing tray in place on the reservoir lid and marked the center of the ebb & flow kit holes. 

I installed the kit.

I then made two holes in the reservoir lid. A large hole to accept the pump. And a smaller hole where the overflow riser would drain back into the reservoir. 

I used a 25 watt pump rated at about 500 GPH. This pump did not have such high flow that it could get ahead of the depth riser. If it had, other steps would have been required to limit the flow, but it turned out that the fact that these magnetic drive pumps are capable of very little pressure worked to my advantage. The increasing back-pressure of the nutrient filling the grow tray progressively slowed the flow with the pump intake adjustment near minimum until it was circulating fresh nutrient but draining the overflow just about as I wished.

In my larger ebb and flow trays, I had used an 800GPH pump moving nutrient up from the floor, and I had to use a ball valve to prevent the flow from overrunning the riser and flooding out of the tray.

Some shimming with the foam was required to allow the pump to rest on the bottom of the reservoir and to level the growing tray.

 Depending on your pump size, the tubing may have to be adjusted for length. When level, there were foam shims at front and back between the grow tray and the reservoir. 

 

One nice feature is that, because the reservoir lid is recessed, any leaks at the riser and fill connectors will just collect in the lid and drain back through the service port. The service port is made lightproof using a 2” net cup with a clone collar. The fit is loose enough that leaks can drain into it. The pump power cord can just run under the edge of the lid. So, there are no holes in the body of the reservoir. There have not been any leaks, but because of this arrangement, they cannot escape the reservoir lid.

 I filled the grow tray with LECA just beyond the point where the depth riser would be draining the overflow. 

A test run with water showed that it maintained that depth during the fifteen-minute flood period. 

 

I then added another layer of LECA. This layer is above the flood and stays dry and therefore does not grow algae. 

 

I added nutrient and set the timer to flood for fifteen minutes every three hours. I have learned that beyond three hours, LECA begins to dry, and I want it to retain moisture to protect roots. I left it to cycle that night. The next day, I adjusted pH and planted shallots in one tray and mixed day neutral onions in another. The third will be an experiment in carrots, using Parisienne/Nantes carrots which are ball shaped and hopefully will not be so sensitive to the medium characteristics that caused regular carrots to twist into knots. 

 

The finished unit is about 34” x 18” and about 15” tall. That brings the tops to a good working height under the lights, which supplement the natural light in the greenhouse with its heavily matted clear panels.