Hello Mary. I'll attempt to answer your questions! I'll just tackle them in the order you ask.

1. Is the yield lower?

This is somewhat of a subjective question, as there are many things to be factored into the answer. The short answer is: as long as you still feed/fertilize, water, accommodate the plant's lighting needs, and plant the plant in a big enough pot, the yield should be no different than what you'd expect in the ground. Remember that the root system of a plant can grow to be three times the size of the plant you see growing above ground!

2. Do they need to be watered more often than plants in the ground?

Honestly, it depends mainly on the kind of pot you are using. Terra cotta? Ceramic? Ceramic material will absorb less water, which means you'll need to REPLACE the amount of water LOST to absorption and subsequently evaporation LESS often than you would if you were to plant in a terra cotta pot. Plastic obviously absorbs very tiny amounts of water, if any at all. If I were you I would do myself a favor and stop comparing potted plants to ground plants honestly(: There really are few comparisons in technique, and it might become dangerous to keep comparing them. Just focus on those in the ground and those on the pots as separate entities entirely, and care for each "as needed", combined with these guidelines(:

3. Do some plants do better in the ground vs. pots or vice-versa?

Yes. Vertical space (both ways, above soil and below soil!) is something you should always be mindful of. For example, it may be problematic to grow corn in pots because of how tall the plants get. Now what I mean by both sides of the soil is this: You mentioned planting some root veggies - specifically radishes - in pots. This CAN work, so long as you make sure you have very deep pots set aside for this variety. Take what I told you before about the importance of being absolutely POSITIVE your plant has enough room for its root system, multiply the importance of that times ten, buy pots according to the importance of that, and you'll be fine(:

As for it being too early to start a spring garden in Portland, the answer is yes, it may be. Not for sure, but possibly. Even here in central California I "play it safe" and do my entire garden in transplants as opposed to directly sowing seeds into the ground. Even here in California, only a few crops will grow to maturity if you wait til the weather is direct-sow friendly.

Good luck!
-Noah

I primarily use containers, be it a SIP/SWC or a 5-gallon bucket. Plants in containers always need more attention than their in-ground counterparts because of the container's natural tendency to dry out easily/quickly. The yield can be just as prolific, depending on how well you nurture the plants. I hit my 5-gallon tomatoes w. Miracle-Gro every two weeks

Here is one of my tomato plants from May 2011:
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And another one from June 2011:
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And, I forgot to mention before that one way to take maintenance down on container plants is to follow this plan:

1. Use pots that are the same size and height, at least per species. In other words: all tomatoes get an 18" tall pot, all peas get a 12" tall pot, etc.

2. Buy large boards of plywood and white paint.

3. Line all your pots up in groups how you want them (if you have ten tomato plants, you may want to line them up, fine in one line, five in another, maybe have the lines of pots 6 inches apart from each other.

4. Mark on your plywood where to cut "slots". The slots should be cut in such a way that you will allow you to position the large, white board of plywood so that it completely covers the top of each pot, effectively blocking hot sunshine from reaching the soil, yet still allow the stems of the plants to stand straight up, undisturbed. It's crazy how much of a difference it makes in terms of evaporation and whatnot!

I've grown a lot of vegies in containers near Portland :).

Yes, you have to water MUCH, MUCH more. In the Northwest, you can water plants in the ground once a week or so (a deep soak), but plants in pots need water pretty much every day, once the weather warms up. Rain doesn't count unless it is pouring.

My number one bit of advice is that you water from the bottom, not by pouring water into the top of the pot.

Water from the top tends to run down the inside of the pot and leave the center, where the plants' roots are, bone dry. The soil can look nice and moist on top and the plants still dry up and die.

There are lots of ways to do bottom-watering. You can set each pot in a dish or tray, at least an inch deep (2 or 3 is better). Unless it's over 100 out or your dishes are very tiny, you can probably get away with filling the dishes once a day. But you cannot skip a day, not when it's really summer out.

Or you can put a group of pots in a child's swimming pool. Or you can make 'self-watering containers' (google that) which are basically two plastic buckets or tubs inside each other, with water in the outer one and provision for it to get into the inner one where the plant is, but not too quickly.

Or there is a new-to-me method making the rounds on the internet, using rain gutter material and a toilet float. You can google that one, too.

All of these methods mean you can reduce your watering to once every 3 or 4 days, unless we get a super-hot spell. The last two have too much startup labor for me to bother with, but the gutter one is pretty cool if you want a project :).

My bell pepper plans are incredibly prolific in pots-one advantage is I can get them outside a few weeks before last frost because they can be taken back in on cold nights.

Tomatos do extreemly well (more than I could eat) in 5 gallon buckets.

Summer squash of various varieties give great early yields and then stress when the temps get really warm so you never get the exceptionally heavy yields you would expect with things like zuchini.

Snow peas will grow in anything. I swear if you have an inch of soil and plant at the right time you will get healthy beautiful snow peas and a ton of yield-at least where I live. I have planted 20 pods in a single dish pan and had them all sprout and grow to produce peas.

In addition to all the above info I'd suggest you check out the Container Gardening forum here . I direct linked it for you below.

As that is the focus of that forum you'll find a great deal of good info on types and sizes of containers to use, which varieties work best, what container mixes to use, as well as the unique watering and feeding requirements for containers.

1. Is the yield lower?

Yes. The larger the container used the less the reduction in yield.

2. Do they need to be watered more often than plants in the ground?

I would have to say a definite yes to that one. Again, the larger the container used, the less frequent the watering required. The same holds true for fertilization.

3. Do some plants do better in the ground vs. pots or vice-versa?

Yes, most any plant will do better in the ground than in a pot. But again, the bigger the pot the better the plant will do. Some varieties of each plant will do better in containers so use varieties that are bred for container growing.

See the theme here? BIG containers. That is the most common mistake container growers make - using too small containers.

Dave

Here is a link that might be useful: Container Gardening forum

I've only got a few years of gardening under my belt..and I do not claim to be an expert in any way. But I would keep small things to my containers whenever possible. Try to do the herbs, maybe smaller peppers and cherry tomatoes types in pots...bigger stuff in the beds.

Last year I did Japanese Black Trifele ( sp? ) in 5 gallon buckets..the first tiers of fruit came out great ( picture below )...but by the end of the season the last groups of fruit were weak and much smaller. I liked carefully removing the plant to inspect the root system and found it to be totally pot-bound in a 5 gallon bucket. The tap root had found it's way out a drainage hole and bored into the ground beneath the bucket. ( Probably also why my last groups of fruit suffered ).

This year Im just doing Bell Peppers and Borage ( Blue and Albino ) in Buckets...and making an attempt at trellising small Winter Squash like Red Kuri and Delicatas.

So...my advise is this ~ experiment! Edison found 2000 ways NOT to make a lightbulb before he found a way TO make a lighbulb. If something works for you please share.

Thank you so much for the feedback. The take away is to use large pots and water/fertilize often. Unfortunately i planted the radishes in small 7" pots and they have already sprouted and i can't move them. I shall plant the next batch in larger pots.
sjkly mentioned planting Bell pepper plants in pots. I have planted them in the ground in the past years and get really poor yield out of them. I wonder if it is the time zone I'm in?
I shall post my progress as the season advances.

Thanks once again. If you have any more advice please pass it on.

I never did any container gardening until a few years ago, because I have plenty of garden space available. Quite a few of my urban friends and family members were having problems growing container vegetables, so I decided to take on the challenge and find out why they were struggling. I very quickly found the main problems and how to avoid them. My container gardening is now another fun but out of control hobby. :)

The following are my observations and opinions regarding why my acquaintances were not being successful:

1.) Pots were undersized. I agree with others that this is the number one problem. Follow established container size guidelines for specific varieties. If in doubt about a pot size, go larger. A person must also be willing to adjust mid-season and carefully transplant a plant into a larger container if the current one is found to be lacking. Container gardening is not necessarily a "plant once and watch it grow" hobby.

2.) Plants were not being watered enough. Often during the heat of summer, containers will need to be watered as much as twice per day depending on the circumstances. If plants are wilted every day by watering time, chances of success diminish rapidly.

3.) Plants were being placed in very hot microclimates. Container plants in full sun on the south side of the house on a deck or patio on a 90 degree day will cook, roots and all. Heat-stressed roots do not happy plants make. Doubters should simply place a thermometer where the plants are and check the temperature a couple of times between noon and 3:00pm on a hot, sunny day. Trust me, vegetable plants are not happy living in 120 degree temperatures. Best scenario is as much full sun as possible, avoiding the hottest part of the day with the highest sun angle. Easier said than done, I know.

4.) Not enough sun. Full-sun plants need full sun. Half a day is not good enough. This issue should take the number 3 comments into consideration.

5.) Container plants can have high fertilizer requirements, but folks should know what they are doing. Dumping a bunch of miracle grow on your plants because "it is good for them" is not a recipe for success. A little bit of self-education is important here.

6.) Plants not given enough general attention and maintenance. Container plants need quite a bit more attention than garden plants. They should be inspected every day for disease and watering issues as well as maintenance such as pinching, pruning, staking, tying, etc. Anyone who attempts container gardening because they think it is "easy" or is a shortcut or way to "cheat" will soon be disillusioned. Personally, I have never understood this attitude. Why bother with plants if you are not interested enough to watch them grow and care for them?

7.) Be realistic. In most cases container vegetables simply will not produce as well as their garden counterparts. This is not failure. Experience will advise a person what to plant more of next time in order to compensate for reduced yields.

8.) Try to use container varieties bred for the purpose, and dwarf types if available, as well as vining types that have been bred for a bush habit rather than vining habit. As skill level increases then certainly experiment with true garden varieties. Experimenting is one of the joys of gardening, but not with the plants that are expected to provide fresh produce for the dinner table. Baby them and you will be rewarded with good eats.

Good luck, and have fun.
-Tom

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Excellent info Tom!!

Mary please understand that when we are talking about really big pots we aren't talking about the usual flower pots rather 10-15 gallon containers or larger, 1/2 whiskey barrels, Earthboxes and similar, etc. A few things can do well in 16-20" diameter pots but any smaller than that quickly become problematic for much of anything other than some dwarf varieties, herbs or small flowers.

Look into what are called Smart Pots (fabric containers) and BIG self-watering containers. Read all the posts on the Container Gardening forum how to build Earthtainers (31 gallon self-watering containers). And if you have a recycling center near you they can be a good source of all sorts of cheap big containers.

Many folks pick up 45-55 gallon drums ($8 here), clean them well, have them cut in half and some large holes drilled in the bottoms for drainage, add a decorative coat of paint, and grow anything you want in them.

Dave

I think you could grow 2 or 3 radishes happily in a 7" pot. 3 is pushing it and 4 is probably too many. Thin them and they will be ok :).

I tried lettuce in a window box and it is doing great. Tomatoes didn't do well last year in 3 gallon pots, very few tomatoes harvested. Rosemary and Basil did really well in a 3 gallon pot last year.

Hi Mary,

Use your beds for as much vertical growth as possible (trellised) for Cucumbers, Tomatoes, peas and beans. Keep your containers for peppers, eggplant, and prolific greens like Swiss Chard and Collards. Also, herbs like Basil and Dill do really well in containers.

There are "patio tomatoes" that are pretty good producers. They are just for containers! Nancy

The comment about hot microclimates is spot on.

The ideal location will have good morning sun and be shaded from about 1pm to 4pm.

That said I've been container gardening for over a decade with only 4 hours of afternoon sun on a southern facing deck. Makes it harder and changes what you need to do for planting mix, container, & watering routines.

I'd recommend against SWC, which I did for 10 years, and instead go with handwatering or automatic drippers. Some people use SpotSpitters or Netafim spray spikes. I'll be changing over to these this year.

These links show one form of vegetable container gardening:

http://lowcostvegetablegarden.blogspot.com/2012/09/eggplant-stump-branch-pot-comparison.html

http://lowcostvegetablegarden.blogspot.com/2012/09/pepper-containers.html

Here is a link that might be useful: Organic vegetable container gardening pictures