Hi Grace,

What is the approximate ratio of clay to compost to use?

Thanks

Well, I’ve used about an inch of compost all over the soil, covered by two to three inches of mulch, but some people say to use more mulch. When I’ve dug up perennials, I put several handfuls of compost in the hole and mixed it with the native clay and then planted the plant back in that soil mix keeping it higher up. The heavy clay will break down or “eat” the compost over time so that’s why you need to keep adding mulch every year. It’s all approximate.

If water doen't pond,plants are usually ok unless poorly adapted to begin with. Here's what happen's during extended rainfall ( which is happening in Texas as we speak and no end in sight) . Clay soil swell's when saturated then repel's additional water which trikles away to the creeks and rivers. Sandy soil alow's continued absorbson which aften soaks several feet below surface and raises stored water level. If bedrock or other impremiable layer is near surface,it act's like a bathtub which can indeed kill plants. If a hole can be dug 2 feet deep without water seeping in,you have little to worry about. Adapted plants wilt but spring back soon as sun come's out and dries surface.

I think the problem here is that since all of the plants were planted recently, those that are not doing well have haven't adapted yet, and my concern is that they won't ever due to improper soil. For example, some salivias that should be easy to grow are not doing well (meaning they have not grown at all after 6 months).

you are best off not amending planting holes ...

first.. perk your soil and find out what drainage you have.. if any ...

https://duckduckgo.com/?t=ffnt&q=garden+soil+perk+test&iax=videos&ia=videos

if your soil doesnt perk.. meaning the water doesnt move away .. then adding anything in the hole that holds water... peat.. compost.. etc ... only makes water retention worse ...

in bad draining clay.. you should plant a pot about half way into the clay .. and then mound good draining soil around it ... then.. the plant has draining soil above.. and eventually it can put its roots into the clay ...

usually.. clay is a very good soil for plants.. every plant sold as ball and burlap is grown in clay .. otherwise the ball would fall apart immediately ...

so basically... you should work in raised beds ...

if you want to amend clay .. you must amend the whole bed.. not just the holes you plant in ....

ken

ps: adding sand to clay equal adobe ... it doesnt help anything..

@ken_adrian Adrian MI cold Z5

I know that amending the whole bed and not just the planting holes is common advice, however, the best local nursery around me does recommend amending planting holes because our soil is pure clay. I think the reasoning is that by the time the plant‘s roots want to expand beyond the plating hole, the mulch will have worked its way down and loosened the soil so that the plant doesn’t become root bound in the hole. I specifically asked about this issue even for planting shrubs and that was their best advice for shrubs too, because our soil is so clayey that non natives pretty much can’t get established without amendments. I must say, this approach has worked for me so far. Our soil eats mulch incredibly quickly. Obviously amending the whole bed would be best, but some amending is necessary when planting non natives. I now have about 5 in of dark friable soil in only 3 years and a really lush and not root bound garden. I know the shrubs are the real test, but they are doing great too. The shrubs that I didn’t amend are just sitting and not really growing while the ones which I amended the soil are really growing fast.