If you are growing in pots, you need potting soil or a soil-less mix sold specifically for container culture. Containers - regardless of what is grown in them - need a very textural and fast draining yet somewhat moisture retentive soil. The 5-1-1 mix referred to endlessly on the Confiner Gardening forum (5 parts bark fines, 1 part peat, 1 part perlite) is pretty much ideal. Or any sort of bagged mix that approximates that formulation. Any nutrient requirements for containers are supplied by the grower via fertilizers, not through the soil (as with raised beds).

And no, rocks do not assist with container drainage - they actually impede good drainage and simply serve to raise the perched water table.

I agree on the potting soil mix. I would then add a good complete organic fertilizer like Fox Farm All-Purpose, Dr Earth Tomato & Vegetable, or Down to Earth All-Purpose Mix.

Here is a challenge - how will you stake /stabilize the tomatoes in the pots? For determinate tomatoes you could use a standard tomato cage; but with the light potting soil you will need to bury the legs deeper into the pot than you would in garden soil. Indeterminate tomatoes present the toughest challenge. You don't have enough soil in the pot to secure a support for vines that are 7 to 10 feet tall. This often requires some kind of trellis / stake / cage structure that is anchored outside of the pot.

Great question. I thought a chage might work, but it sounds as though you don't think that will be structurally sound enough to work. Anyone have any ideas or experiences with this?

thanks for the soil help to you both.

I've grown ind. tomatoes up to 8' tall in 4-5 gal. plastic pots and they did quite well. Instead of cages I supported them by wrapping the tomato stem (as they grew) around jute twine suspended from the roof framing over my back porch. On most of the plants I kept the suckers pruned so as to have a max. of 2 main stems. Got about 30 or more tomatoes from each plant. Most were Early girl variety.

Harry

To grow tomatoes and peppers in pots requires a fairly good sized pot, not a 1 or even 5 gallon pot will do. These plants will need a very extensive root system to produce enough fruits to be worthwhile. A pot that large will then support a good sized trellis.

kimmq is kimmsr

I grow my tomatoes in containers as well and one indeterminate variety will fill a 25G black nursery container easily by the end of the season. And a regular tomato cage works perfectly well for that size container. I agree that a 5G container is a bit tight to get the best performance from any indeterminate tomato. Watering and fertilizing become much more of a major issue with such limited root space.

I would also suggest that a granular organic fertilizer such as the several referred to above is not your best bet for the most successful container growing. Container soil - potting mix - contains NO real 'soil' and minimal decomposable ingredients so the occurrence of a healthy microbiology is just not present and a healthy, densely populated soil biology is what is needs to process the dry organics. Without the microorganisms to digest and process the ferts, they are unavailable to the plants and are just wasted. If you want to stick with an organic product, look for a liquid - although even these are not completely water soluble (don't require processing by microbes to release nutrients), they will at least provide some good. Most horticulturists and experienced container growers leave 100% organic gardening for inground situations and rely on a well formulated (with trace elements) synthetic fertilizer like one of the Dyna Gro products for any container culture..

Kinda stemming from part of m_gold's original question, regarding putting rocks in the bottom of a planter/pot, does anyone know where this practice originated? I mean, if it's bad for drainage, why is it recommended? (That's not rhetorical, I'm genuinely asking.)

chaparralgirl

Putting stone, rocks, sand, something to "promote" drainage in the bottom of pots, containers, is often recommended by people that have no real idea what they are talking about. I have not seen anything from someone that has studied horticulture suggest that be done.

kimmq is kimmsr

I expect it originated a long time ago and it's just 'what people do'. As a kid I thought that was the right way too. Now I realize it does nothing at all for containers with holes in the bottom. The only possible benefit might be when there are no drain holes, in which case the spaces between gravel could provide a reservoir for extra water so the roots aren't soaking in it. But pots with no holes are not a good idea in the first place, IMHO.

People have all sorts of habits they don't know where they got or why, but they think that's the way to do things. Tapping the top of a soda can before opening so it won't spray foam...composting in pits instead of on top of the ground...cranking the thermostat higher when you get home so the house will warm up faster...warming up the car...the list is endless.

A lot of gardening information gets passed on by word of mouth, whether it has any validity or not. And growing plants is really a science and science makes new discoveries and advances everyday, many of which disprove these old word-of-mouth practices.

Garden myths abound - conifers make the soil acidic (NO!); you should always add compost or improved soil to planting holes (NO!); you should apply sealer or paint to pruning cuts (NO!); rocks, gravel or pot shards in the bottom of a container improve drainage (NO!); don't get water on plant foliage during the heat of the day as the sun will "burn" the leaves (NO!), etc., etc., etc.

OK. So why don't the rocks help?

I certainly see the logic; rocks presumably protect against compaction at the drainage hole. Except it's counterproductive. Why?

rocks, simply, take away scarce soil space. I have started growing peppers in pots two years ago, they have small roots cmp to toms, can be put in a really warm spot (my garden is in a local cold microclimate), my solution is to put a dozen earthworms and earthworm food in the pot (some kitchen scraps and leaves), together with good soil from under my 8 years old pile of leaves (basically dark clay). Drainage is fine and so is nutrient availability, and I can reuse the soil in winter as a sprouts medium. Be organic, use nature's micro-tillers.

I agree glib, it mainly takes away space that could be used for potting mix. I do put a broken pot shard over the bottom holes esp. if they are large, just so the soil doesn't come pouring out when I water. I used curved pieces so they don't seal off the hole but just create a bit of an umbrella effect over it.