COMPOST, MANURE OR MULCH CONFUSTION

macfall

I have shurbs and perennials in my border.  Originally about five years ago I created a border.
I have clay soil and I put plenty of manure and compost in.  Up to now the soil has been ok, These last year the weather has been strange and the perennials under the a pine tree did not do very well.  In the spring, I am thinking of putting some compost and mulch around the plants to contain the moisture.
Do I put the compost then the mulch on top, and how often does the soil need manure.  Which compost manure or mulch would you recommend.  I live on the North west coast.  

didyw

Hi @macfall.  It has been a very strange year - a late spring, prolonged periods without rain...  But I think we need more information - which perennials do you have under your pine tree and what is the aspect? (eg, are they in sun or in the shade of the pine - how big is the pine and what species, is your soil acidic or alkaline?). A pic would help. 
It sounds like you prepped your soil well with compost and manure so a mulch of organic matter - well rotted horse manure, composted material from your compost bin, leafmould or similar laid thickly on top would help keep the soil in good heart.

raisingirl

Mulch is a technique rather than a substance, and you can use either well rotted manure or garden compost to do it.
Mulching is spreading a thick - 2 to 4 inches - layer of an organic material onto the surface of the soil. You should avoid mulching right up to the stems of most plants (a mature tree probably won't care) but otherwise, the aim is a thick coverage across a bed so there is no bare soil visible.
If you have a supply of well rotted manure, including the stuff you can buy in bags from a garden centre, then it's probably the best you can do for most plants. The exception will be ones that don't like too much richness in soil, such as Mediterranean herbs (eg lavender). You can also use garden compost if you have enough of it or bark chips.

The stuff that garden centres sell as 'compost' is generally not a great mulch, being light (so it blows away), generally including some soil and/or peat and therefore actually a good growing medium for weeds seeds. You can buy 'soil improver' in garden centres and these usually are suitable to use as a mulch.

The best time to add mulch is the autumn, after rain, so I wouldn't wait until spring. You may need to water the ground under your pine tree - that's a very hard environment for most plants to grow as pine trees take all the food and the water they can reach. Possibly those plants may need to move - if the tree was planted 5 years ago and so has matured in that time, it's possible that the perennials were OK there while it was young, but now it's getting bigger, they are finding it harder to survive. Mulch will help, for sure, but if they are actually under the pine tree canopy, you may need to move them.

BobTheGardener

I agree with @raisingirl and would have said exactly the same.

nick615

To the last two posts, am I right in thinking that leaves falling from trees and other shrubs have two purposes in nature, i.e. to return some of the nutrition held in them to the surrounding soil for re-absorption, and to keep the root stock warm - or is the latter a romantic Granny tale?

Fairygirl

I've never heard of the latter @nick615. Mots roots wouldn't like being warm.
I'd also agree with everything @raisingirl said. 
Under a pine tree can be tricky for growing anything, unless there's enough moisture, enough soil, and the planting can cope with the needle drop all year round.

raisingirl

@nick615 leaf fall is a natural autumn mulch. Many people seem to spend a lot of time and money raking up leaves and disposing of them and then buying mulch, when they could just leave the leaves and save themselves a lot of bother and expense. (Collecting fallen leaves in order to compost them is a different thing and definitely worth doing if you have the time and space).
The roots of a reasonably mature tree will be more than a metre below the surface and at that depth, the temperature actually doesn't change much seasonally apart from in the most exceptional weather years so no, I don't think the leaves keep the tree itself warm in winter. If you leave the leaves on the ground they will, as a mulch, protect smaller plants from the frost to some extent and more importantly, they will provide cover and food for soil organisms which, in turn, does help the tree by helping its local eco-system

nick615

Thanks for clearing that one up, raisingirl.  I'd always wondered.

Jac19

That is because the tree branches shade both the sun and the water from getting to the perennials planted under it.  And also the strong tree roots dominating the soil and starving the smaller plant roots under it to some extent.  I have the same problem under my trees.

So, retention of whatever water they get under there will help.  Compost can be dug into the soil.  The perennials will want good drainage in clay type soil.  Hence, it is a good idea to add in some horticultural sand/grit with it.  John Innes No. 3 compost comes with quite a bit of h. sand/grit and loam which help drainage.  When there is drainage and water gets down below, carrying plant nutrition with it, the plants can send roots deep under for water and nutrition.

Mulch in the farmyard manure at the top.  Once every couple of months will do.  This is the one I buy.

https://www.wickes.co.uk/Gro-Sure-Farmyard-Manure---50L/p/132290

Lyn

Whoever buys compost with JI to dig into the ground! 

floralies

I rather thought we had sorted that one out a while ago @Lyn, obviously not!!