Probably not a good idea because algae and other things may grow in your rain barrel over the period of a month even if the barrel was in the shade. I'd really worry about bio fouling, especially since a 64 gallon rain barrel is a lot of water!

@ewwmayo I guess you could fight that with small amounts of chlorine, but then you run into all kinds of complications understanding what doses of chlorine different plants can tolerate.

It is a real drag to make all this fertilizer weekly. Is there any practical way to automatically dispense it?

Opt instead for a controlled release product, at least for any woody plants. A one time application each spring should get you through the full growing season.

I only use a liquid fert on my houseplants, containerized veggies and any annuals. All the rest of my containers - assorted trees, shrubs, vines and perennials - get dosed each spring with Osmocote Plus. It releases all necessary plant macro and micro nutrients over a period of 6 months.

@gardengal48 I know you are not big on fertilizing succulents, but I cannot deny that Dyna-Pro 9-3-6 creates a very significant difference if used lightly every week, on my container succulents. The plant in the photo below looked very unhealthy and small, and as soon as I started the Dyna-Pro it just took off. I would say 80% of the succulents are like that. In contrast, Osmocote Plus just does not produce the same intense results. I wish there were a way to automatically dispense the 9-3-6 in a dilute concentration.

I am not very god with fertilizing, but it is easier in summer: I use a hose (and water from rain barrels as long as it lasts), and attach Hose end sprayer. For succulents, I put in usually less fert than recommended for garden, or use it after I watered most of my veggies - assuming fert solution is weaker (it gets lighter in color). I do not know if that is god enough, but, so far, so good.I decided to do this recently, since I hardly ever fertilized my succulents - and want to see if they grow better-bigger, which I am sure they do :).

I also use large watering can - it holds over gal of water, and water as many plants at once as possible (I am sure some ppl would say it isn't good idea to pour water over the plants - but I do. I do it almost always while plants are outside, and have done same for years..There are very few that I water individually - for example pot of Lithops.). I do not make and store any solution ahead of time.

Or, maybe you can mix all needed at once, in a bigger bucket. Enough to fertigate all plants you want to. Then it can be used with smaller watering can if you want to water each plant individually. What do you use for watering?.

As Kevin said, storing diluted solution is a not a good idea. Beyond a few days it will develop algae. Storing in dark container can slow that down.

I use miracle grow universal feeder gizmo. The device attaches to your hose tap and has bottle to hold the liquid fertilizer. Although the bottle is intended for one time use, it can be easily reused to dispense any other liquid too. You can carefully pop the nozzle thingy and fill it up. I modified mine though to make it easier to add liquid to the bottle. I made a hole on the other side and glued a 1/2 inch pvc tube with a cap. Works very well. The only thing is that it is a fixed dilution rate. I think it is 1:325 if memory serves me right. That comes to about 2.3 tsp per gallon. That is the max rate. You can dilute the FP to get to desired rate for say 1tsp per gallon if you want. The device is quite accurate.

Since then I have modified it even further. I created a a wood frame to hold two of them in series to dispense two liquids. I use the first one to dispense Protekt or sometimes vinegar and the second one for FP. I have several modified bottles that I can use to switch the liquid. Eg outdoors I use seaweed fertilizers once in a while.

If you want a commercial one look for Dosatron. They are expensive $300+ Nurseries and greenhouses use them. They are adjustable and far more robust.

This is how I fertilize my potted plants: http://dramm.com/html/main.isx?sub=458

Vlad, I used to use that syphonjet. Just FYI it is not consistent under various conditions. The dilution ratio depends on pressure and flow rate. More problematic is the flow rate for me. For small potted plants I throttle down the flow rate a lot so as not disturb the top soil much. But then it does not draw much or any fertilizer. Also the limit of hose length after the syphon is 50ft which may not be a problem for many but it does for me. The best way to use it is actually right at the end of the hose instead of the beginning. It is far more consistent. But then one will have to drag a dolly with the contraption. Syphon mixing works great in farm/greenhouse situation where you can fix the pressure and flow rate for a specific zone.

Syphon mixing will also work if you are filling a bucket for hand watering situation since you can use the full flow rate to get consistent dilution.

I happened by and saw this.

I currently use a watering system in the garden that uses a tank. This develops amazingly few problems, now that I think about it--the EZ-Flo system, meant for hose-end systems, and I only clean it out once or twice a year and do add kelp to the system so you'd think it would be a sloppy mess. It isn't.

But I don't think a rain barrel system would be adaptable to it, although I'm not sure what all the system options there are.

Premixing in a barrel or bucket open to the air I did try once. Once.

The mess was...kind of not very nice, so I don't recommend it. At lower concentrations, it's an algae trap. You can add an anti-algae tablet, but that's not exactly great for the plants, either.

Complete isolation from sunlight will defeat that, so covering your rain barrel will stop algae and cyanobacteria from growing, if you can manage isolation from all light. That's difficult.

At higher concentrations of food, the salt ratio does keep the algae at bay because they can't survive it. So if you make a concentrated solution and dilute it down for use, that would actually be fine. But it defeats the purpose of keeping a ready-made solution around for immediate use. Hence the siphon mixing idea from TropicOfCancer.

How do you normally mix your 16 gal of solution each week?

I used to mix in a 4 gal sprayer but that was too much work. These days I mix into 6x27L (7 gal) plastic tubs and bottom water my succulents. It's a little wasteful but it saves me a lot of time and effort.

Can someone explain what doses of Dyna-Gro 9-3-6 would go into an automatic dispenser or a similar device like the DRAMM? When I fertilize, I am using approximately 1/2 tsp in 1.5 gallons of water. That container then fertilizers about six plants (I try to not over-use it), which would be about 0.25 gallons per plant. Large plants get a double dose. I do flush the containers thoroughly with just water prior to fertilizing.

The DRAMM video says to use one gallon of fertilizer for every 20 gallons of water. Well, that clearly does not work when the fertilizer is Dyna-Gro. If the ratio is 1:20, then my 1/2 tsp of Dyna-Gro in the automatic dispenser would only give me 10 tsp of water, and that would represent a massive over-concentration of the Dyna-Gro.

@rina Currently I mix 8 gallons at a time, and then I pour from that larger container into the 1.5-gallon dispenser. I could mix 16 gallons in a small garbage can, but then how do I pour out from that? Ideally, I would want that can on a stand and to have a spigot at the bottom.

@tropicofcancer Can you show some photos of your custom engineering on the dispensers?

@ewwmayo Can we see a photo of how you are using that tub? How do you carry it around?

westes

It is easy to install spigot and really worth it...if I can do it, I am sure you can. I have 9 barrels (50gal to 65gal), and they all have tubes (4 are attached to each other) and 6 have spigots. They are on a stand (that I built). I used to scoop water out of the barrels with a smaller bucket (that fit thru opening). It is so much better to have spigot!

You are mixing 8gal at the time - similar to ewwmayo.

Tropic, I have had no problems using a siphon. I install the siphon at the end of a 100 foot hose and before 30 ft hose. I also use a Dramm 170PL Water Breaker, as instructed by the manufacturer. That water breaker provides a stream of water that is gentle enough to meet my needs.

Westes, you need to make the solution 20 times more concentrated than what you would normally use. So, if you are using 1.5 Tsp/1.5 gal: 20 X 0 .5 Tsp/gal = 10 Tsp/1.5 gal.

@vladimir I still do not get it. I use roughly 15 gallons to get the entire container garden fertilized. So call that 5 tsp of liquid Dyna-Gro into 15 gallons. Now I want to end up spraying the same 15 gallons onto the plants. Using your siphon what volume of water and fertilizer goes into the container?

In your example with 10 tsp / 1.5 gal, assume that concentration is inside the DRAMM tub. How many gallons of fertilized water can be sprayed from that concentrated solution?

@westes Zone 9b California SF Bay - They are clear shallow storage bins, like what you would put under the bed. For my potted trees, I sometimes pour one of the bins into a large watering can so I can water them separately. On my deck, I don't have to move them around so when finished I just dump them.

For measuring the amount of liquid fertilizer, I use a graduated syringe with long dispensing tip (no sharp point). That's something very simple that makes it more convenient.

@ewwmayo Okay, so you have a storage bin with seven gallons of fertilized water. How are you dispensing that? Do you have a spigot installed at the bottom of the container? Are you elevating those storage bins above the watering level for the plants?

@Vlad: Good strategy. I have the 170PL breaker too and it is quite gentle. One of the best. There is another one that has yellow color which is apparently more suitable for bonsai.

westes

Since ewwmayo didn't answer so far, here is what he posted couple of days ago:

..."These days I mix into 6x27L (7 gal) plastic tubs and bottom water my succulents. It's a little wasteful but it saves me a lot of time and effort:...

@rina I do not understand what he means by bottom watering the succulent. I imagined water coming out the bottom of the bucket, which could be done by installing a spigot. But I want the details.

@westes Zone 9b California SF Bay My plants are kept in perforated plastic trays. I just set the plant trays into the larger plastic tubs and water that way.