Limestone...and lots of it.

[Thomas CA]

This morning I dug out an old bush to make some more room for more tomatoes next year, and hit this large area of limestone underground.

The chunks were about hand-size and very soft (I could break them open with my hands).

Now, I know garden lime and limestone has it's place in the garden as an additive, but what can I do with this, if anything? Should I just forget using this area? OR will this stuff be good for the soil?

[img]https://img263.imageshack.us/img263/4682/dsc03496z.jpg[/img]
[img]https://img718.imageshack.us/img718/2141/dsc03497m.jpg[/img]

[jal_ut]

I would not worry about the stone you dug up. You can plant something there and see how it does. You can do a soil test if your are really curious about the state of that patch of soil. For me it would be, "add some compost and plant something."

[Dillbert]

pick out the big chunks / sift out the medium chunks (optional)
plant.

limestone per se does not necessarily "make the place alkaline" - it just sits there, pretending it's a rock, until something acidic comes along then it does its smash&grab neutralizing thing.

have you had the surrounding area(s) checked for pH?

[Thomas CA]

Duly noted.

There's some pretty large slabs a bit deeper down I'd like to try and get out. These chunks may have been part of something larger.

I have a tomato row about 10 feet away that's tested 6.0-6.3.
I grew a cucumber plant next to the bush last year, to use it's long branches as a trellis, and it seemed OK, but not the best producer.

I think the bush I pulled out really liked this stuff. It had roots going into the crevices and small root balls around them.

[TZ -OH6]

Iv'e never heard of limestone that you could break with your hands like that, and I don't remember seeing anything like that in the native rocks around Palos Verdes (although there was planty of Gypsum). How far are you from the DDT dumpsites (Torrance) where people were digging chunks of that out of their yards?

[Thomas CA]

Well, I'm guessing limestone as it matches some of the descriptions I found, particularly chalk-like limestone.

There's a block in the ground about 3'x3' and who knows how deep. I can jab my shovel into it and break off moist chalky shards.

I'm down at the southwest side of the mountain. I believe the old DDT dump from way back when was done on the other side of the peninsula, about 20 miles off shore.

Now I'm not sure what this stuff is. some sort of deposit.

[Kisal]

Chalk is what it sounds like, from your description. There are chalk deposits in your area, from what I've read.

You could call your city engineering office and ask them what it might be. If you don't feel comfortable with that, contact the nearest university and talk to someone in the geology department.

[Des_WA]

Hard to say what it is from the picture; limestone isn't generally breakable by hand unless it's extremely weathered, and even then...

If I had a better picture I might be able to help (I am a geologist ). Otherwise I'd second calling a local college or university and asking their geology department for some info on your area soils/bedrock.

[applestar]

Well, if it IS more alkaline there, what might be good to plant? Carrots and beets would have problems with the rockyness, but what about lettuce, spinach, chard, peas...?

[garden5]

I kind of wonder though, would large chunks of limestone have the same alkalining (not a real word ) effects that pulverized/granular garden lime would? Your soil may not be that alkaline at all.

[ThomasCA]

I had asked a neighbor, who recently had their front yard redone, if they had seen this in the soil, and he stated yes. Apparently it's calcium carbonate deposits (limestone in soft-chalk form) and can be found all around the peninsula, as the cliffs around me are loaded with old sea creatures, shells, etc.

I'm wondering if I could grind this stuff down to suppliment any needed calcium for my tomatoes.

As for now, I think I'll try planting some shallow rooted stuff in this area.
Perhaps I'll give a cucumber a go or maybe some pole beans to see what happens.

thanks all for your guidance and comments.