annuals that like poor soil

Hi -

I've just moved to a place with a balcony and patio, and am hoping to have boxes and baskets before too long (this is our first slightly warm weekend here in Chicago)! However, I've read that some flowering plants like petunias and nasturtiums prefer "poor soil" because if it is too rich, they will have many leaves and relatively few flowers.

Does this mean that if I planted them in something like the locally-available potting mixes (which often have a little slow-release fertilizer), then they will not have many flowers? And if that's too rich, is there some way I can make the soil "less good"? I don't have a yard to be able to just scoop up random dirt :)

Thanks for any input I can get! Sorry if it's kind of a silly question...

Hi Scuba,

First, it's not a silly question at all. What causes excess green green growth at the expense of bloom is too much nitrogen. The fertilizer in most commercial mixes is a balanced Osmocote - like fertilizer so I would not worry at all. I've grown many petunias in these mixes. Have fun!

Victor

I've wondered the same thing, but I think (just like Victor said) that potting mix isn't all that high in nitrogen, even when it comes with added fertilizers.

Random dirt isn't so great for containers anyway, because you can get into issues of insufficient drainage & aeration... You are fine with any decent potting mix, with or without the added fertilizer. I use Pro Mix, which doesn't have added fertilizer, but then I add moisture crystals and osmocote to it... and nasturtiums, petunias, etc. have all flowered themselves silly in my windowbox planters!

We did have an issue one year with tomatoes... built a new raised bed (more like a really big container; the back portion where we put the tomatoes had 2 feet of nice topsoil), and there was just too much N in the nice mix of compost and topsoil that we used... We had absolutely enormous vines and almost no tomatoes at all! But potting mixes with peat moss & perlite won't have that kind of N boost to them, so you'll be fine.

I'm envisioning your balcony looking like a jungle by the end of summer.... what fun! I lived in Chicago, and I just cherished the plants I was able to grow on my windowsill... sure would've loved a balcony! (I did have a potted ginko tree taking up too much space in my cubbyhole of a kitchen, but hey I needed the green more than I needed to be able to eat at the tiny table occupied by the pot!)

Thanks so much!! Now I can take my friend up on that offer to pick me up a humungous bag of soil at Costco, and not plan on skulking around the neighborhood digging at night. :) I can't wait for summer!