Straw thank you for the detailed answer. If I start crushing black eyed peas for the roses - my husband will think I have gone nuts. As it is he thinks my garden related stuff has taken over our house.

• Weekly liquid fertilizing with Epsom Plant Tone or Tomato Tone once the weather gets hot & dry: Do you use as directed on the package or do you dilute it?

• Since the weather is still in 60s/70, until end of this month, with scattered rains, what do you recommend I feed the roses.

• Do I need to replenish the application of azomite, cracked corn and alfalfa straw or is one application per rose bush good enough until fall?

• I noticed few leaves turning brown. It looks different then bs. Do you know what it is and how I can prevent it. I have attached the photo.

Runerat: I tested red-lava-rock for 2 years, and decide NOT to use it. It takes tons of rain to break it down, and with heavy clay, you DON'T NEED red-lava-rock, due to its high pH. The heavier the clay, the higher the pH of soil.

Red-lava-rock works best when buried to neutralize the acidity of acidic soil, but it didn't work in heavy and alkaline clay. The paleness of your leaves is from high-pH of red lava rock. And the black-spot on the leaf is from high pH which makes copper and zinc less available (both are anti-fungal agents). I got that black-spot on leaf when I used too much red-lava-rock, and it's NOT a fungus, will have to check what's the excess in red-lava besides high-iron.

Azomite has high pH of 9, same with red-lava-rock. I would TAKE OUT the red-lava-rock, and that will solve the problem.

Azomite is once a year application. Azomite supplies trace elements, plus calcium. Acidic spring rain (pH 5.6) will neutralize its alkalinity. Azomite works best for pots (mostly peatmoss & lacking trace elements) .. but I don't think heavy clay need that.

Alfalfa hay can be used often, it functions as a nutritious mulch to keep roots moist. Cracked corn is useful in dry & hot summer, as an acidic filter to neutralize alkaline tap-water. Roses don't bloom in my heavy clay in hot summer, no matter how much tap water given. But it bloomed when I spread cracked-corn on top, as an acidic filter to lower the high pH of tap-water.

When I state SOLUBLE fertilizer weekly in hot & dry, I mean SOLUBLE POWDER such as sulfate of potash or gypsum to lower pH of tap-water. SOLUBLE fertilizer comes from water passing through and breaking down cracked corn or alfalfa hay, or from making alfalfa tea.

Rose-tone & Plant-tone, and Tomato-tone are GRANULAR fertilizers meant for once-a-month in pots ... that won't be dissolved in tap-water, since it has bone meal and chicken manure. A rose nursery uses that GRANULAR "rose-tone" once a month for their pots, and weekly DILUTED soluble such as chemical MG SOLUBLE.

Clay is rich in minerals, thus Azomite and red-lava-rock won't be necessary, unless you have acidic clay, which is less heavy than alkaline clay. Heavy clay is different than pots, it retains nutrients too well, so the chicken-manure in Rose-tone & Plant-tone & Tomato-tone will burn in hot & dry weather, plus the bonemeal in that mix can't be used at pH higher than 7 .. it just sit on top and stink up.

What works for heavy clay with spring rain? Alkaline Azomite works well, since it's a powder which dissolve easily in rain, to neutralize the acidity of rain. Rose tone & Plant-tone & Tomato-tone as GRANULAR fertilizer will also break down with acidic rain..

What works for heavy clay in dry & hot weather with alkaline tap water? Sulfate of potash has 21% sulfur which helps to dissolve in alkaline-tap. Acidic cracked corn worked well as a filter to lower the pH of tap water. Alfalfa hay works well in dry & hot weather ... it acts as a mulch to keep roots moist.

When organic breaks down, it releases acid to neutralize alkaline tap water, plus to break down the hard minerals in clay into usable nutrients for plants.

I check on what's in excess in red-lava, besides high pH which cause pale leaves and black patch on lowest leaves. There are 2 sites, and I trust the 1st site more, since it's from Oregon State University. From Wikipedia: Red-lava rock is alkali basalt is relatively poor in silica and rich in sodium.

Sodium is same as salt, so the black-spot on your leaf could be from excess salt, either from too much Azomite and red-lava-rock. Azomite has many trace-elements, so less than 1 tablespoon per large bush is enough. Alkali basalt rock like red-lava would be lacking in aluminum and higher in salt.

http://volcano.oregonstate.edu/what-lava-made

http://www.palmercc.com/lavarock.htm

Gosh, I love the info you post Miss StrawC!

It's all starting to click. I have powder sulfate of potash to save for summer. I'm thinking I need that Spring application of Azomite to counteract the recent rains and fungus spurt. Question: What can I use in place of wood ash? Azomite?

Hi aztcqn: Glad to hear from you .. I have been admiring your pics of orchids, cactus, and succulents. When I bought Azomite I first tested in a pot, it was too salty for my tiny rose-rooting (shorter than my little finger) .. the salt and FAST RELEASE of Azomite killed 2 rootings. But Azomite worked well in tiny amount to supply trace elements for BIG rose bush, Marie Pavie was much healthier last fall than previous years, thanks to Azomite. Another person made the observation that Azomite helped with fungal diseases in rain.

Wood-ash is known to damage roots if it's not neutralized by rain in compost.

Best choice was pea-gravel (pH over 8). I tested that in a vase with cut-blooms against red-lava-rock, Azomite, lime, gypsum, sulfate of potash .. and pea-gravel kept the cut-flower perky instead of leaves breaking out in blackspots with prolonged soaking in water like regular tap water.

No harm was done with slow-released minerals in chunky size, but fast-release fine powder like Azomite, gypsum did damage when I used too much. Gypsum gave 4 of my roses bad rust (orange-fungus), and I had to top roses with alkaline clay to reverse the damage.

Since pea-gravel is composed of a variety of colorful minerals, I spent hours researching on the pH of different color. Thanks to the guy who tested the pH of water when he used pea-gravel in fish-tank. He posted that when he used beige pea-gravel (like the color of the great Pyramid, which is composed of limestone) ... beige or yellowish pea-gravel shot up the pH of tank, and his fish didn't like that. But when he used black or dark-gray pea gravel, it didn't shoot up the pH of water. The red-pea gravel has higher iron, doesn't release minerals as fast as the beige one.

Pea-gravel is sold cheap at local store for $3 a HUGE 40 lb. bag. Amazon sells that cheap at $2 per lb., plus $5.25 shipping. Amazon's pea-gravel is mostly dark-gray. Pea-gravel is used in cactus mix, see below reviews on Amazon:

http://www.amazon.com/Miniature-Fairy-Garden-Fine-Gravel/dp/B007NKEJXO/ref=cm_cr_arp_d_product_top?ie=UTF8

Thanks StrawC,

Interesting, I use pea gravel in my cactus mix. They like a more acid mix. I've been using mostly rain water for them and they are quite fat and happy. I suppose it balances the PH overall. :]

Thank you StrawC for all the research & tips. You are a walking encyclopedia on roses.

Runerat: No problems .. I like to share my mistakes as well as success. Please let us know how your roses turn out with different additives. I want to double-check to see if things work the same or different elsewhere. Thanks !!

I was about to return that big bag of red-lava-rock to the store, and get bagged soil instead .... but I dug up a dozen dandelion-weeds in my lawn, and the place where it's topped with red-lava-rock, the dandelion has 3-forked roots, rather than one elongated tap-root .. made it hard to kill.

Branching of roots below, or branching of branches above result in more blooms & more bushy. The 1st sign of phosphorus deficiency is reduced branching of stems, thus less blooms.

One website advise NOT to give one's lawn potassium fertilizer, since it makes the tap-root like dandelions more aggressive. There's one bed which I mixed gypsum with red-lava-rock into my clay. then sown mustard seeds .. all of them sprout & healthy despite this dry & hot week. There's another bed which I threw seeds down on my clay, and topped with potting soil .. none sprout, all died.

Two years ago I used cocoa-mulch NPK 2.5 - 1 -3 (high potassium), plus sulfate of potash on my tomato, plus Tomato Tone NPK 4-6-6 ... plenty of potassium which made my tomato REALLY SWEET. I made pasta-sauce with that, and didn't need to put sugar in.

Last year I used sulfate of potash only ... tomatoes were sweet, but crop production was 1/10, since I forgot to put Tomato Tone in the planting hole. I can't taste roses, but I can taste tomato to see the effect of different fertilizers.

It was a nuisance to give soluble sulfate of potash, so I'll experiment with red-lava-rock in the planting hole for tomato .. will report the result. Someone else reported how red-lava-rock helped seedlings:

http://www.permies.com/t/6671/organic/volcanic-ash-fertilizer

"When I lived in 'country' on the beautiful isle known as Oahu we used to take actual lava rock from a 'special source' which turned out to be very air lava rock. We would cut the rock, and use it to start seedlings in because it made the very best and safest seedling starter out there. The roots of what we were planting at the time would grow through it, and break it down over time." Mekka Pakanohida

Below is the minerals listed for red-lava-rock:

Mineral Content

Nitrate Nitrogen.................................4.0 p.p.m.
Phosphorus........................................6.0 p.p.m.
Potassium.........................................59.0 p.p.m.
Zinc.........................................................6 p.p.m.
Iron..................................................10.0+ p.p.m.
Copper...............................................5.5+ p.p.m.
Magnesium.......................................2.0+ p.p.m.
Boron.................................................10.0 p.p.m.
Sulfate.................................................7.0 p.p.m.
Organic Material...........................................5%
PH.........................................................8.2 Units
Calcium..................................1.3 Meq/100 gm*
Manganese...........................0.6 Meq/100 gm*
Sodium...................................0.1 Meq/100 gm*
Cation Exchange Capacity..3.2 Meq/100 gm*

strawC: I'm so glad to see an update on the lava rock. I was about to remove them from my roses. I went looking for sulphate of potash & have not found them in either HD, Lowe or our other big nurseries. Is there a brand you recommend from Amazon? Also what brand of alfalfa meal do you recommend & where can I buy them? We do not have any feed stores around. I had brought my alfalfa straw from the rabbit section of Petsmart. I went to get some more & they were out of it instead they had some fake looking hay.

Hi Runerat: For sulfate of potash, I buy this brand from Amazon, at $9 for 1 lb. But it takes only 2 teaspoon to induce way more blooms. I sprinkle that around the bush before the rain. Sulfate of potash should be used with calcium in 2 to 1 ratio. But if your soil is heavy clay, there's plenty of calcium already.

http://www.amazon.com/Potassium-Sulfate-Potash-Organic-Pound/dp/B004JD6MGK

Alfalfa meal? It depends on your soil ... that's fantastic for fluffy & loamy, or sandy soil, but it tends to glue-up on top of heavy clay. I get Standlee alfalfa pellets (no salt, no sugar), and it has a clean & fresh smell, rather than stinky and dusty like alfalfa meal. Google "Standlee alfafa" pellets .. hopefully you can get that on-line. I have to call my feedstore a week in advance, they order it for me, then I come to the store to pick up.

Red lava rock lasts at least 10 years to provide potassium. A decade ago I dug a large trench across my garden, filled that with 3 bags (40 lbs. each) of red-lava-rock. I meant to stop the invading pink-yarrow but it backfired ... the flowers went nuts, and 2 neighbors complimented me how fantastic my flowers look.

Ten years later, I killed all the pink yarrow, and planted few hundreds of daffodils across my garden. The daffodils bloom lots where the red-lava-trench used to be, but gave one-fourth the amount of blooms elsewhere.

Vintage Rose Garden (out of business) used to top their bands with crushed-red-lava rock for iron. In alkaline condition (heavy clay), manganese, iron, boron, zinc, and copper are less available, so red-lava-rock helps. Too much on top can give leaves a reddish & brownish tinge.

To crush red-lava-rock: I bagged 3 layers of brown-grocery bags, fill that with red-lava-rock (pre-soaked in rain-water), then put a big stone on top, then jump on it to crush. Then I mix that in the planting hole, so I don't have to worry about potassium, iron, boron, zinc, and copper for years.

Thank you for the link on the sulfate & alfalfa meal & more tips on the lava rocks. Your neighbors are lucky. They get to see your beautiful garden everyday!!!

Runerat: I researched on red-lava-rock as growing medium in hydroponics (without soil) and folks report good result. Last summer I piled up too much red-lava on Stephen Big Purple rose, and the leaves did turn reddish when heavy-rain broke it down too fast. But no harm was done, I simply removed the rocks. This spring, Stephen Big Purple was the earliest to come out of zone 5a winter, means very robust root .. thanks to red-lava's high potassium.

I'm going to test red-lava with tomato this year to see if it improves the taste. High potassium suppose to make tomato sweeter. Red lava rock raises the pH very slowly, compared to faster pH rise of pea-gravel, Azomite, and lime. Some info. from hydroponics forum:

http://forums.gardenweb.com/discussions/1984422/using-lava-rock-as-a-growing-media

" happyhydro

I grow 60 5 gal buckets of tomatoes in a DWC recirculating system.6in net pots with lava rock. The lava rock is an essential part of this systems success. Provides beneficial bacteria culture which hooks the plants up with nutrients and wards off bad bacteria.."

robert_1943

Expanded clay and Scoria is a tried and tested method giving very good results.
I have changed from a flood and drain to drip system with these 5 containers , which prevents over watering and easier to control. These tomato seedlings are Heritage Arkansas which I am trying for the first time they were grown from seed and are two weeks old.
I am using part A and Part B dry mixture which I make up into 2x11 litre containers with taps for easy use to add when required ..

*** From Straw: the pic. above belongs to Robert in hydroponics forum. His tomatoes look great, using red-lava as growing medium.