Less Water and More Heat.

What chemicals should I put into the soil to insure a good crop of vegetables, such as tomatoes, string beans, or other over-ground producers?  Last year my tomatoes and string beans grew plentifully, but never produced any tomatoes or beans, yet turnips and parsnips were all right.

Vegetables which behave like your tomatoes and string beans, making too much growth and not enough fruit, do not need fertilization.  The land is perhaps too rich already, or you may have used too much water.  Use less water so that the plants will make a more moderate growth, and they will be fruitful if the season is warm enough in the later part of summer.  This, of course, would be one of the drawbacks to growing tomatoes and beans in San Francisco.  Turnips and parsnips do well with less heat.  You may have to modify the San Francisco summer climate by wind screens or glass covers.

Continuous Cropping With the Same Plant.

What would happen on the crops of cucumbers, tomatoes and eggplants, etc., planted on the same place continuously?

There would be in time a decadence of crop from soil exhaustion, but that you could prevent by fertilization.  The greatest danger from continuously growing these vegetables on the same land is the multiplication of bacteria which injuriously affect them, in the soil.  The plants which you mention are all subject to “wilt” diseases from this cause, therefore, they should have new ground.  If you have to use the same garden ground continuously, the plants which you mention should be rotated with root crops or with other kinds of vegetables, so as to frequently change plants and soil within the general area which has to be used for them.

Big Worms on Tomatoes.

I have a nice patch of tomatoes in my garden, and only recently I notice large green worms on them with one large brown horn on their head.  They strip the leaves off.  They look to me like a tobacco worm.

They are tobacco worms; that is, they are the larvae of hawk moths, some of which take tobacco, tomatoes, grapevines and many other plants, including some of the native weeds of your valley.  Pick them off and crush them, or give them a little snip with the scissors if you do not like to handle them.  They are so large and easily found that such treatment is easily applied, as in “worming tobacco.”

Loss of Tomato Bloom.

I have tomato plants which are very strong and healthy and full of blossoms, but there is something cutting the blossoms off and just about to ruin my plants.