compost in containers?

15 years ago

Background: Tomorrow is the plant sale a my local community college, and they will have student grown native/drought tolerant plants - and they will also have lots of heirloom tomatoes, among other veggies and herbs.

Now, I won't be able to have an extensive garden this year, just a few things in containers. They are giving away free mulch/compost.

Will it be okay to use this in the containers as the sole or at least primary growing medium? or should I be using mostly potting soil with a touch of the composty mulchiness ?

Dawn in the High Desert of Southern California

Sort by:Oldest

Comments (5)

buzzsaw8
15 years ago
Lots of different opinions on this, mine is that it's a bad idea. It breaks down into pudding-like mess before the season is over. Also retains too much water. This leads to root-rot.

If you're not up for making your own mix (pine bark, perlite, little bit of peat), I'd probably say to buy regular Miracle Grow potting mix and amend it with lots of perlite.

The free compost is awesome for raised beds or for dressing your lawn though.

There's a container forum here at GW too, you might want to read some threads there. This guy "tapla" knows a little bit about container plantings.
justaguy2
15 years ago
Compost in containers is generally a bad idea and leads to slow/poor growth for many plants.

I will say that of the plants that can be grown in it and still do at least OK tomatos are among them.

That you live in a desert climate means things will dry out faster than they will for most of us so I think you will be OK with compost. Not ideal, but OK.

Please skip the mulch in the mix though. That will just tie up nitrogen and lead to poor growth. You can use it on the surface to aid water retention, but not in the mix without large potential for nutrient problems.
Related Professionals
Surprise Landscape Contractors · Dickinson Landscape Contractors · Hoover Landscape Contractors · Kaysville Landscape Contractors · Lancaster Landscape Contractors · Paramount Landscape Contractors · Pine Hills Landscape Contractors · Whitehall Landscape Contractors · Everett General Contractors · Spencer General Contractors · Waianae General Contractors · American Fork Decks, Patios & Outdoor Enclosures · Baker Decks, Patios & Outdoor Enclosures · Greeley Decks, Patios & Outdoor Enclosures · Saint Louis Park Decks, Patios & Outdoor Enclosures
aliceinvirginia
15 years ago
If you do use compost in tomato containers, what sort of percentage would you recommend? 10% or less?

Alice
guardenman
15 years ago
Well this is one of those open ended questions. Compost is organic matter. All (good) soil has organic matter in it. Most likely if you bought a commercial potting mix, it already contains the proper amount of organic matter to grow plants in a container. Adding more will throw it off and end up with poor results. If you make your own potting mix, well of course you need to add compost.
Then you will start getting into the different types of compost. If you make compost with peanut dust you can grow plants in just that. If you make it with leaf matter you need to add some wicking materials, like perlight or peanut hulls or the often dissed (bark) mulch. If you make it with discarded food, than I would have to hold it in my hand before I could tell you what to add.
It sounds like you are spatially limited, so you may not be able to experiment, but if you have the room for some failure, I highly recommend playing around with making your own soil mixes. You will learn a lot about how roots work, if you do it. Just remember you will have some failures along the way.
jessicavanderhoff
15 years ago
Do you think potting soil really has enough nitrogen to grow tomatoes? It's made for all plants, and tomatoes need a lot more than most things, right?