New Grass in Shade with Acidic Soil

[Smolenski7]

I had a pro at Valley Green today suggest that bc I have a Maple, Weeping Willow, and Pine tree all growing within a small area that the soil is probably so acidic it causes the grass I've planted over the last several years to die away after germination. He suggested a soil test and most likely a heavy application of lime before I seed again. He also suggested aeration bc the roots from all 3 trees are compacting the soil. Any thoughts on this?

[Green]

I would take the advice with a grain of salt, because: 1.) It's someone trying to sell something (or more than one something). 2.) They haven't seen your property. 3.) They're going by a bit of this and that chopped up and mixed together in a pot.

The truth: We tend to have acidic soil here, regardless. I heard an explanation recently; there are many factors at play, not just one or two simple ones. Of course, the only way you would know is by doing a quality soil test (which you may already have done, but didn't mentioned whether you had).

A "heavy Lime application" means different things to different people. But it's not something that should be done without a soil test, and ideally not right before seeding, producing a situation where it's going to be in contact with the new grass as it germinates. pH correction (if it's low) will most likely take some time. And low does not mean below 7. Ideal soil pH is arguably a bit acidic. A pH in the low to mid 5s is low (and needs attention if you want grass to grow).

Aeration is not going to make holes in tree roots (nor would you want holes in your roots), so I fail to see how that would help. It might just damage the aerator and roots, and not much more. I've never heard of tree roots compacting soil around them, but I'm not very knowledgeable about trees.

Regardless of the above, Fine Fescues have shown better performance than most other species not only in shade and root competition situations, but in acidic soil as well. I know a lot of people don't like it, but it's a useful grass, and arguably the best choice sometimes.

[bpgreen]

I'm not sure what the trees have to do with acidity, but getting a soil test from Logan labs and having it interpreted here is never a bad idea.

I don't think tree roots compact soil. Aeration is rarely necessary.

[Smolenski7]

Thanks for the information. The soil is compacted, so he is right about that. I think I would rather do something else rather than a mechanical aeration though. Any suggestions?

Yes. A soil test definitely needs to be done. I don't know the pH in that specific area, but I'll find out soon.

[andy10917]

Smolie:

I know "Green" recommended taking the advice with a grain of salt. I would advise that you take it with a pound or two of salt - the guy at VG repeated every hackneyed piece of poor info on the planet.

[Smolenski7]

Smolie:

I know "Green" recommended taking the advice with a grain of salt. I would advise that you take it with a pound or two of salt - the guy at VG repeated every hackneyed piece of poor info on the planet.

Then any suggestions as to how to grow grass in this area? Because of the 3 trees I mentioned originally, it's pretty densely shaded. I can get it to germinate, I just can't get it to last from year to year. Maybe its just too shaded?

[andy10917]

The combination of shade and competition for water and nutrients is pretty damned tough on grasses. You can try to lift the canopy some by having lower branches removed so more sun gets to the grass blades.

Here's a general rule for figuring out where grass stands a chance - stand under the tree where the canopy is widest - the root zone comes out roughly the same distance as the canopy.

Over years and years of trying (and often failing) to get grass to grow under trees, I have learned to let my hosta, Vinca Minor, and Pachysandra have the space directly under trees. Yes, I have succeeded in growing KBG under trees, but I don't think it's worth the battle and large amounts of time invested.

[Smolenski7]

The combination of shade and competition for water and nutrients is pretty damned tough on grasses. You can try to lift the canopy some by having lower branches removed so more sun gets to the grass blades.

Here's a general rule for figuring out where grass stands a chance - stand under the tree where the canopy is widest - the root zone comes out roughly the same distance as the canopy.

Over years and years of trying (and often failing) to get grass to grow under trees, I have learned to let my hosta, Vinca Minor, and Pachysandra have the space directly under trees. Yes, I have succeeded in growing KBG under trees, but I don't think it's worth the battle and large amounts of time invested.

Thanks, Andy. I've thinned the trees and have lifted the canopy as best I can. I think they are just getting too big. The neighbors Pine blocks the morning light, my Willow blocks the afternoon light, and my Maple (and even a small fence) blocks the sun late in the day. I can plant hostas around the base of the trees, but to go out as far as the canopy is just not practical.

So, even amending the soil won't help?

[andy10917]

No. Sunlight is needed for the plant to make its food, and water is required just stay alive. And don't forget that trees are very aggressive competitors - a mature Maple can use 40,000 gallons of water a year.

[MorpheusPA]

Totally agreed. As the years spin on and my trees get larger, the area that gets relegated to mulch underneath them gets larger. Someday I may sit down and plant things other than spring bulbs (that grow very nicely before the trees leaf in), but not right now.

I just figure it's more area I don't have to have the mower mow.

[lVlrBoJang1es]

random side thought - anyone watch the Masters?

Notice how their pristine grass (though painted and dyed) grows right up to the trunks of their trees?

Also notice how their trees are shapped like lolli-pops? No branches until you get to the 30+ ft mark... Tons of sun light at the base! Easier turf management i'd assume in addition to the aesthetics...

Also notice how one of their massive trees fell, almost on the patrons?

Lots of things to notice

[MorpheusPA]

Yep, golf lawns tend to be some of the most manipulated greenswards on the planet. Not to mention some of the most toxic, but that's another story.