Question
Hello, I was wondering what the advantages of greenhouses are over being grown in open area.  What I know is that they keep the temperature inside hot and they keep out chemical and GMO pollen drift (for organic produce).

Also, how do you find out the optimal soil pH's for different kinds of vegetables and how do you maintain the same pH levels for the whole area?

What is the square foot method of gardening?

Thanks, Tim

Answer
Greenhouses are use for controlled climate conditions and to keep out pests.  They are predominantly used in the winter months to protect plants from frost.  They also give gardeners a head start in winter on their plants prior to transplanting to the garden in the spring.

Garden centers sell test kits for ph and fertilization levels.  The ideal ph is 7.0, which is considered neutral.  But all plants vary in their needs, and some respond better to low ph while others do best at higher levels.

If the ph is below 6.5, the soil is acidic.  You can counter this by adding lime to the soil.  On the other hand, if the soil is above 7.5, the soil is higher in alkiline.  This can be corrected by adding sulfur. A good rule of thumb is that soils west of the Mississippi are usually alkaline; east of the Mississippi are generally acidic.  Gardens high in organic matter seldom need adjustment.  Another strong argument for organically amended soil.

Square foot gardening is a method of intensive gardening. The term "square foot gardening" was coined by an American author named Mel Bartholomew who wrote a book under that title.

Quite simply, this method utilizes vegetables and flowers planted very close in proximity, and grown in raised beds which are framed by natural non-rotting wood such as cedar. The beds can be structured anywhere from 2'X4' to 4'X12', with the most common configuration being 4'X4'.

The advantages to this method are as follows:

1. The soil stays friable since you never walk in the beds.
2. You can harvest many more vegetables since you're planting in blocks instead of rows.
3. The beds are much easier to water since there is no waste between rows. The same hold true for fertilizing.
4. Less weeding since there are no rows between plants and every square foot is dedicated to vegetables.
5. Easier pest control.
6. Rotation of crops is done by bed instead of location.
7. The beds are more aesthetic, and far less work.
8. No tilling each spring.
9. Trellises are structured at the north ends of the beds as a means to save even more space by growing vining plants such as peas, beans, and squash vertically.

Here are examples of what can be planted in each square foot:

9 onions, beets, bush beans, bush peas, garlic, or spinach.
16 carrots or radishes.
4 lettuce, chard, marigolds, or kohlrabi.
1 tomato, pepper, eggplant, broccoli, cabbage, or corn.
1 squash, cucumber, or melon per 2 sq.ft.
6 vining plants such as beans or peas on trellises.

This method works well in all parts of the country, and is becoming increasingly popular every year.

I realize this can't begin to explain all that is involved in starting a new garden. That is why I strongly recommend investing in one or two good books on the subject. There are numerous ones on the market, but the one I really recommend is "Square Foot Gardening" by Mel Bartholomew. It can be found on the web or at your local bookstore. Also, feel free to use this forum again should you have any other questions or run into any problems.

Attached is a website that will give you additional information on the subject.

http://www.squarefootgardening.com/

Good luck with your garden, and thanks for writing.

Regards,

Mike