You could not reasonably expect dynamite to transform the character of the surface soil except as its rebelliousness might in some cases be wholly due to lack of drainage — in that case blasting the hardpan might work wonders.  But you have another problem, viz:  to change the physical condition of the surface soil to prevent the particles from running together and cementing.  This is to be accomplished by the introduction of coarse particles, preferably of a fibrous character.  To do this the free use of rotten straw or stable manure, deeply worked into the soil, and the growth of green crops for plowing under, is a practical suggestion.  Such treatment would render your soil mellow, and, in connection with blasting of the hardpan to prevent accumulation of surplus water over it, would accomplish the transformation which you desire.  The cost and profit of such a course you can figure out for yourself.

Is Dynamite Needed?

I have an old prune orchard on river bottom lands; soil about 15 or 16 feet deep.  Quite a number of trees have died, I presume from old age.  I desire to remove them and to replace them with prune trees.  I have been advised to use dynamite in preparing the soil for the planting of the new trees.

Whether you need dynamite or not depends upon the condition of the sub-soil.  If you are on river flats with an alluvial soil, rather loose to a considerable depth, dynamiting is not necessary.  If, by digging, you encounter hardpan, or clay, dynamiting may be very profitable.  This matter must be looked into, because the failure of trees on river lands is more often due to their planting over gravel streaks, which too rapidly draw off water and cause the tree to fail for lack of moisture.  In such cases dynamite would only aggravate the trouble.  Dynamiting should be done in the fall and not in the spring.  The land should have a chance to settle and readjust itself by the action of the winter rains; otherwise, your trees may dry out too much next summer.

Improving Heavy Soils.

What is adobe?  What kind of plants will grow best in adobe?  In this Redwood City I find clay-like soil which looks very dark and heavy.  What kind of plants will grow best in this soil?

The term adobe does not mean any particular kind of soil.  It is applied locally to clay and clay-loam soils indiscriminately.  It generally signifies the heaviest, stickiest, crackingest soil in the vicinity.  Most plants will grow well on heavy soils if they are kept from getting too dry and too full of water.  This is done by using plenty of stable manure and other coarse stuff to make the soil more friable, which favors aeration, drainage, root extension and plant thrift.  Friability is also promoted by the use of lime and by good tillage.  The particular soil to which you refer is a black clay loam which can be improved in all the ways stated.  It is a good soil for most flowers and vegetables if handled as suggested.  You can get hints of what does best by studying your neighbors’ earlier plantings.