I need marketing statistics on a hot new trend in gardening – people
who are growing vegetables in containers (i.e., small pots or
containers that fit on porches or windowsills or even in the house).
How many Americans are now doing this? Is this trend increasing? What
is the projected trend to be in one, three, five, ten years? How much
are these Americans spending on these containers and necessary
supplies to grow vegetables?

Many of the statistics you need may be found in the National Gardening
Survey, which is available for $495:

http://www.nationalgardening.com/RSRCH/report.asp

Here's a smattering of information from the 2001 National Gardening
Survey:

Container Gardening Sales Reach $1.2 Billion in 2001 

Container gardening is the fastest growing consumer lawn and garden
sales category in terms of household participation, average amount
spent, and total sales we have seen over the past 5 years. Five years
ago 10 million households participated in container gardening, and
today that number has grown to 23 million households. The average $
spent by consumers on container gardening 5 years ago was $43, and
today it's $55. Total retail sales for container gardening products
(plants, pots, growing medium, and fertilizer) was $387 million five
years ago, and today it's over $1.2 billion. We expect this strong
growth in container gardening to continue in the future.

Here's a look at who spends the most on container gardening: 

Women (64% of sales)
Men (36% of sales) 

18-34 year olds (19% of sales)
35-44 year olds (28% of sales)
45-54 years of age and older (26% of sales)
55 years of age and older (27% of sales)

College graduates (56% of sales)
Some college (37% of sales)
High school or less (7% of sales)

1 person household (33% of sales)
2 person household (51% of sales)
3-4 person household (15% of sales)
5 or more person household (1% of sales)

Whites (82% of sales)
Blacks (6% of sales)
Hispanics (5% of sales)
Other (7% of sales)

Northeast (24% of sales)
Midwest (20% of sales)
South (30% of sales)
West (26% of sales)

Household income of $75,000 & over (35% of sales)
Household income of $50-$75,000 (21% of sales)
Household income of $35-$49,999 (14% of sales)
Household income under $35,000 (14% of sales)
Undesignated (16% of sales) 

http://store.yahoo.com/nga-gardenshop/25-7200.html

Thanks, pinkfreud-ga (great name!). The facts you quote here are right
on ... tantilizing ... and where can we get ADDITIONAL facts just like
this, WITHOUT paying $495 for the National Gardening Survey. And where
did you get your hands on a 2001 edition of the NGS (the latest I have
been able to find in a 1999 edition)? Also, the link you posted at the
end leads to the NGA membership page, and I can  hardly use that when
I have to cite proper references. So carry on ...

Sorry about the bad link. I was juggling a bunch of stuff, and I
fumbled. ;-)

This is the page where I found the 2001 information that I quoted
above:

http://www.nationalgardening.com/RSRCH/feature_may.asp

Several hours of searching has led me to believe that you may not be
able to obtain the information you desire at a price you may wish to
pay; the $495 National Gardening Survey looks to me like your best
bet.

I do not have access to library databases; some other Researchers do
have such access. You might want to post a new question asking whether
anyone can locate a copy of this survey in a library that you could
access.

Good luck!

Oops. Sorry, I just noticed that you had posted a question asking
about obtaining the latest National Gardening Survey:

http://answers.google.com/answers/main?cmd=threadview&id=205963

I've boosted that question to the top of the Researchers' question
queue so that more Researchers will be able to see it. I hope someone
can find it for you.