One Thousand Questions in California Agriculture Answered Part 32

How shall I make a hot-bed to raise sweet potato plants? I don't mean to put gla.s.s over bed, but want full description of an up-to-date outfit for raising them.

Manure hot-beds have been largely abandoned for growing sweet potato slips, though, of course, you can grow them that way on a small scale or for experiment. In the large sweet potato districts, elaborate arrangements for bottom heat by circulation of hot water or steam are in use. In a smaller way hot air works well. The Arizona Experiment Station tells how a very good sweet potato hot-bed at little cost is constructed as follows: A frame of rough boards seven feet wide, twenty feet long and fourteen inches deep is laid down over two flues made by digging two trenches one foot deep and about two feet wide, lengthwise of the bed.

These trenches are covered with plank or iron roofing, and are equipped with a fire pit at one end and short smokestack at the other.

Four inches of soil is filled into this bed and sweet potatoes placed upon it in a layer which is then covered with two or three inches more of soil. Large potatoes may be split and laid flat side down. The whole bed is then covered with muslin, operating on a roller by which to cover and uncover the bed. Thus prepared, the bed may easily be kept at a temperature of 60 to 70 degrees F. by smouldering wood fires in the fire boxes. The potatoes, kept moist at this temperature, sprout promptly and will be ready to transplant in about six weeks. A bed of the size mentioned will receive five to seven bushels of seed roots, which will make slips enough to plant an acre or more of potatoes.

Growing Sweet Potatoes.

Please inform me how to keep sweet potatoes for seed; also how many pounds it takes for one acre, and what distance apart to plant, and the time to plant.

Sweet potatoes may be kept from sprouting by storage in a cool, dry place. Sweet potatoes are not grown by direct cutting of the tuber as the ordinary potato is, but the tubers are put in January or later in a hot bed and the sprouts are taken off for planting when the ground becomes warm and all danger of frost is over in the locality. The number of sprouts required for an acre is from five to ten thousand, and a bushel of small sweet potatoes will produce about two thousand sprouts if properly handled in the hot bed, which consists in removing the sprouts when they have attained a height of five or six inches, and in this way the potatoes will be yielding sprouts in succession for some time. The sprouts are planted in rows far enough apart for horse cultivation. They are usually hilled up pretty well after starting to grow well. They cannot be planted until the danger of frost is over, for they are much more tender than Irish potatoes.

Sweet Potato Growing.

In planting sweet potatoes, do we have to make hotbeds just like those for tomatoes, or if just a plain seed-bed will do? Is it necessary to irrigate them or not?

You can bed your sweet potatoes in a warm place on the sunny side of a building or board fence, and get sprouts all right. You will, however, get them sooner and in greater numbers by using a slow hotbed in which the manure supply is not too large. The fact that sweet potato growers do use some artificial heat, either from manure or by piping bottom-heat in their propagating houses, is a demonstration that such recourse is desirable to get best results. The necessity of irrigation depends upon the soil and its natural moisture supply. On a fine retentive loam, the crop is chiefly made without irrigation, if the plants are all ready to put out in the field as soon as it is safe. If you are late in the planting, or if the soil is dry or likely to dry before the tubers are grown to good size, irrigation, some time ahead of the need of the plant, is essential.

Sweet Potatoes.

What kind of soil and climate does it take to grow sweet potatoes, and can I grow them in any part of Contra Costa county, and about what time is the best to plant them?

Sweet potatoes do best in a light warm loam which drains well and does not bake or crust by rain or irrigation. Sprout the tubers in a hot-bed or cold-frame in February and break off the shoots and plant as soon as you are out of danger by frost. Sweet potatoes are more tender than common potatoes. There are places in Contra Costa county where they do well, though some parts of the county do not have enough summer heat.

Sweet Potatoes Between Fruit Trees.

I am expecting to grow a fall crop of about twenty acres of sweet potatoes. The land is a heavy, sandy loam in the interior, which has been set out this spring to almonds, apricots and prunes. I wish to grow sweet potatoes between trees. Would an irrigation every forty days be often enough? Also, if either sweet or Irish potatoes grown between rows are harmful to either of the varieties of fruit mentioned?

We see no reason why you should not get your crop, providing you do not have to run the plants into the frosty period, and sweet potatoes will not, of course, stand frost as well as the common potato. The moisture which you propose to give ought to be enough for a retentive soil in connection with good cultivation until the vines cover the ground.

Growing any crop between orchard trees is apt to be an injury to the trees, because of the s.p.a.ces which are not and cannot be adequately cultivated, so that the ground around the trees is apt to become compacted either by the run of water or the lack of cultivation, or both. Our observation has been that Irish potatoes are no more injurious than other crops. Any crop will injure young trees if it takes moisture they ought to have or interferes with good cultivation of the land.

Giant j.a.panese Radish.

In discussing sakurajima (giant j.a.panese radish) Eastern publications advise planting late, about August 1, and not earlier than July 1. What can you tell me about the plant here?

The Asiatic winter radishes can be successfully planted in California in July or August if the soil is thoroughly saturated by irrigation before digging and planting. It is, however, not so necessary to begin early in California as at the East, because our winter temperatures favor the growth of the plant, while at the East they have to make an early start in order to get something well grown before the ground freezes. For the growth of winter radishes, then, in California you can wait until the ground is wet thoroughly by the rain, which may be expected during September, and afterward you can make later plantings for succession at any time you desire during the rainy season. This applies to all kinds of radishes.

Rhubarb Rotting.

I have planted rhubarb roots in the San Joaquin valley and find the root crowns rot below the surface.

The old-fas.h.i.+oned summer rhubarb usually goes off that way in very hot localities. If there is too much alkali or hardpan, or if planted too late, the same results will be had with any sort of rhubarb. Where it is very hot, plants, irrigated in the morning near the plants, scald at the crown and die in a few days. If irrigated in the afternoon and the ground worked before it gets hot the next day fine results are obtained.

The winter rhubarb varieties do well in hot districts if the roots are planted from September 15 to May 1, while in cooler sections, April, May, June and July are the best months and will insure a crop the following winter.

Squashes Dislike Hards.h.i.+p.

What caused these squashes, of which I send you samples, to be so hard and woody? They were grown without irrigation.

Your squashes were grown without irrigation under conditions which were too dry for them and became inferior in quality. Possibly the variety itself is not of good quality or the specimen from which the seed was taken may have been inferior. A squash, in order to be tender and acceptable, needs rich feeding and plenty of drink. Otherwise, it is apt to resent ill treatment by very undesirable growth.

Harvesting Sunflowers.

What is the method used in saving or thres.h.i.+ng the seed from the Giant Russian sunflower?

Cut off the seed heads of your sunflowers when the seed seems to be well matured but before any of it falls away from the head. Throw these heads on a smooth piece of ground or a tight floor and when they become thoroughly dry thresh out the seed with a flail, removing the coa.r.s.e stuff with a rake and afterwards cleaning the seed by shoveling it into the wind so that the light stuff may be blown away. A more perfect cleaning afterwards could be secured with a grain fanning mill or a simple sieve of the right mesh.

Irrigating Tomatoes.

How much water does it take (in gallons or cubic feet) to properly irrigate an acre of land for tomatoes? The soil is adobe, and the customary way of planting tomatoes is 6 feet apart each way, plowing a trench of one furrow with the slope of the land for irrigating, that is, a trench between every row and a cross trench as a feeder. The land is low and in the driest part of the year the surface water is from 2 to 3 feet beneath the top of the ground.

It is not possible to state a specific quant.i.ty of water for any crop, because the amount depends to such a large extent upon the retentiveness of the soil, the rate of evaporation and the kind of cultivation. The best source of information is the behavior of the plant itself, bearing in mind that tomato plants require constant but not excessive moisture supply, and that if moisture is applied in excess it will promote an excessive growth of the plant, which will cause it to drop its blossoms and therefore be unsatisfactory and unproductive. In such land as you describe no irrigation whatever would be desirable except in years of short rainfall, and such land, if properly cultivated, would always furnish moisture enough by capillary action to support the growth of the plant.