Northern U.S. Winter Melocactus care

[Kmandarino]

Yes!! I have read that thread several times, very good information there. I'm glad you have picked up the torch. Thank you so much for all of your help, you and the rest of the melocactus gang! Thank you!

[Steve Johnson]

Yes!! I have read that thread several times, very good information there. I'm glad you have picked up the torch. Thank you so much for all of your help, you and the rest of the melocactus gang! Thank you!

You're welcome!

[Steve Johnson]

I would definitely like your fert recipe and instructions!

Here you go...

You'll need the following:

• General Hydroponics FloraMicro 5-0-1 and FloraBloom 0-5-4 liquid fertilizer concentrates. You can buy them at your local hydroponics shop or on Amazon.

• TPS Nutrients CalMag liquid concentrate, available on Amazon here:
  
  https://www.amazon.com/True-Organic-Pla ... 9hdGY&th=1

• Ammonium sulfate and potassium sulfate in powder form, readily available on Amazon and eBay. If you need them in smaller quantities (less than 1 lb.), eBay may be the better place to go. Since you have a small collection, you'll probably want to go with smaller quantities.

• A digital scale measuring down to .01 gram. This is the scale I got from Home Science Tools:
  
  https://www.homesciencetools.com/produc ... g-x-001-g/
  
  Not that expensive, and way better than the cheapo scales we get on Amazon. The scale includes a 200 gram calibration weight you can use to calibrate the scale, and instructions on using the scale are included.

You'll need the scale for this...

Ammonium sulfate-potassium sulfate stock solution

Create a gallon of stock solution by adding 5.78 g ammonium sulfate and 8.4 g potassium sulfate to distilled water or rainwater, not tap or well water. The powders don't dissolve instantly, so be sure to give it some time. When you don't see any particles floating around in the water, you're set. Once the ammonium sulfate and potassium sulfate go into solution, they stay in solution as long as you don't let the stock solution freeze in the winter. Perfectly safe to keep it in the house.

Watering solution

This is for a 1-gallon container. Fill the container about 1/2-3/4 of the way up. Add 1/2 tsp. FloraMicro, 1/4 tsp. TPS CalMag, and 6 fluid ounces of stock solution. Fill the container up to the fill line and add 1/2 tsp. FloraBloom last -- this is step is required to avoid nutrient "lockout" per General Hydroponics instructions. Cap the container, shake well, and water away. The dilutions are per gallon, so if your watering container is 2 gallons, 5 gallons or whatever, change the dilution amounts accordingly.

Dilution = dosage, so we just need to make sure that you're not overfeeding your cacti. And the best way to know is by breaking it down into parts-per-million for each nutrient. Going by the dilutions I just gave you, a gallon of your watering solution will contain:

48 ppm N
14 ppm P
74 ppm K
33 ppm Ca
10 ppm Mg
33 ppm S

The NPK balance is pretty much ideal, and the dosages of all the nutrients are good, so you definitely won't be overfeeding your cacti. The only question is if you'll need to fertilize every time you water them in the growing season. I certainly do because my pumice and granite gravel mix has almost no cation exchange capacity (CEC), so any nutrients not taken up by the roots when the mix dries out go "down the drain" with the next round of water plus ferts and supplements. Fir bark may have enough CEC to where you can fertilize with every other watering, although I can't say for sure. Unfortunately it's too late in the growing season to implement what I have in mind for you, so I'll try to get a good answer one way or the other before you prepare for next spring.

[Kmandarino]

Thank you so much Steve, I will for sure be switching to your recommended fert in the spring. I'm anxious to try it out!

[Steve Johnson]

Thank you so much Steve, I will for sure be switching to your recommended fert in the spring. I'm anxious to try it out!

My pleasure!

I'm rethinking whether or not fir bark is the right organic material for your soilless mix. This came up for discussion in my "Are you growing your cacti in a soilless mix?" thread (if you'd like to go down that rabbit hole, start here -- viewtopic.php?t=47632). Going to page 4 of the thread, our member in Butte County CA (Zac) provided a good and detailed response from John Trager of the Huntington Botanical Gardens:

Hi Zac,

Your mix is not much different than ours in terms of percentage of organic to inorganic. We use 80% pumice and 20% organic. We shifted away from the Forest Humus product for a mix made by a local soils and potting mix company that offers the convenience of mixing it in bulk for us. The pumice we use is the 3/8” size. Here is a link to the organic component. We use their nutrient mix with peat and perlite: https://www.ofwolfinbargerinc.com/soils/.

The organic component can be whatever is available to you locally. LGM planter mix would be good if you can find that. It is largely oak leaf mould. The Forest Humus was a well-composted pine and fir bark medium. It worked well enough but became quite hydrophobic when dry. The same will happen with just about any organic component (like peat) so we try to keep our mix fairly damp and sometimes moisten it before use as needed.

John has been the curator of the Huntington's desert greenhouse for over 20 years -- wizard of a grower. With that said, the Huntington is in Pasadena CA, and the area is more of a desert-type climate. I don't think it's the kind of climate you have in Illinois, so you may be able to go completely inorganic. Here's what my pumice and granite gravel mix looks like:

Pumice-DG_rinsed04242016_forum.jpg (201.76 KiB) Viewed 1029 times

Grain sizes on average range from 2 mm to about 5 mm, and you'll notice the overall consistency of the mix. If you can put a mix together which is similar to what you see, I think your cacti (even Melocactus) would do well with it. And if you don't want to fertilize every single time you water, you can add zeolite to the mix for a small CEC "boost". Per a recommendation I got from out horticulturalist-in-residence MikeInOz, consider a mix of 50% pumice, 40% granite gravel (crushed granite poultry grit will be fine), and 10% zeolite. That way if you occasionally skip on the fert, your cacti certainly won't be starving.

Based on my experience through 12 growing seasons, I found that desert cacti do best when their roots go from wet to completely bone-dry between waterings. Obviously John's approach is quite different, although understandable given his local climate. If you decide to include organic material in a soilless mix, at least he's giving you a few ideas on what to look for. However, let's go back to something he just said:

The Forest Humus was a well-composted pine and fir bark medium. It worked well enough but became quite hydrophobic when dry. The same will happen with just about any organic component (like peat) so we try to keep our mix fairly damp and sometimes moisten it before use as needed.

Apparently he didn't think about the possibility of applying a wetting agent to the organic material, so here's something else for you to consider:

https://www.amazon.com/s?k=garden+wetti ... 5qkodfbq_p

A wetting agent is all you need -- I would steer clear of products which include fertilizer. (Maybe I should bring this up with John?) The idea is that organic material plus wetting agent means the roots of your cacti can dry out completely between waterings, no need to worry about the organic stuff becoming hydrophobic over time.

You have plenty of time between now and next spring to figure out what you'd like to do. If you have any further thoughts or questions, my virtual "door" on the forum is always open.

[Kmandarino]

Thanks for the info Steve. I don't see the point in adding anything that's going to become hydrophobic so maybe composted fir bark is out. ?? As it is, when I water my melos, I also water a pot without anything in it other than the same mix my melos are planted in, in order to monitor the moisture. With the 50% Pumice, 30% Crushed Granite and 20% potting soil, by day 5 or 6, it's dry 2-3" down without a cactus tapping into the moisture. From what I've heard, most melos roots dont like to become bone dry and I would like to water less often and find something other than potting soil which is eventually going to drain out anyway. I don't know anything about Zeolite, maybe someone could educate me on that. Vermiculite comes to mind, but I don't have any experience with that either. Or maybe I just need to stick with pumice and granite and water them often. Just not sure. Sure glad I have all winter to make a decision.

[Steve Johnson]

Zeolite and vermiculite have 2 different functions, vermiculite having the same function as pumice and perlite. However, vermiculite is horrible stuff, so you're better off with pumice. I haven't used a wetting agent myself, and I'm not sure if fir bark is such a good idea unless you're willing to test the wetting agent -- your instincts about not doing it are correct.

Regarding zeolite, read this:

https://www.resilientamerica.us/read-34 ... for-plants

Bear in mind that the article applies to leafy (nonxeric) plants. I'm thinking this like "kinda nice, but not necessary" for cacti, and I don't have it in my mix. If you'd like to give it a try, go with the 50% pumice/40% granite gravel/10% zeolite mix MikeInOz suggested.