THE GARDENING WORLD. 
September 19, 1903. 
804 
Something about Plant Food. 
(By J. J. Willis, Harpenden.) 
(Continued from page 700.) 
There is one' very important factor in regard to plant food 
which should not b® lost sight of j it is this—that while dif¬ 
ferent plants may require the same kind of chemical consti¬ 
tuents to build up their cellular structure, yet. that they require 
these elements at very different periods of their growth, and 
also in different proportions!, according as to whether stems, 
flowers, fruit, or seed is required to be brought into prominence. 
It has, therefore!, been well said by Dr. C. Ii. Goessmann that 
to feed plants intelligently implies possession in a fair degree 
of two kinds of information, namely, a. knowledge of the special 
wants, of the plant under cultivation as regards the absolute 
amounts and relative proportion of the various essential 
elements of plant food, and a familiarity with the composition 
of the different kinds of manorial matters which the gardener 
has at his disposal. 
Bulbous-rooted Plants. 
While every plant cultivated requires nitrogen, potash, phos¬ 
phoric acid, and lime, yet each plant has its especial wants at 
different stages of its development. Thus succulent and 
quickly-growing kitchen vegetables require an abundant supply 
of nitrogen in an available form during their early periods of 
growth, while bulbous plants require more particularly carbon¬ 
aceous matter and phosphoric acid. For example, we find 
that the fertiliser known as superphosphate of lime causes a 
much increased development of the underground or collective 
apparatus of all bulbous plants, especially of lateral and fibrous 
roots, distributing a complete network to a considerable 
distance around the plant, throwing out- innumerable feeding 
mouths to 1 the surface. The extent and direction of the under¬ 
ground range of bulbous plants are at the same time very much 
dependent on the mechanical condition of the soil, especially in 
their early growth, and it is usually acknowledged that good 
tilth is of the greatest importance to the favourable formation 
of the bulbs. 
We know that the best bulbs;, whether of Turnips, Onions, 
Tulips, Lilies, Narcissus, or of 'the Potato tuber, are produced 
in the lighter loamy soils, which are well charged with humus 
matter, and where there is comparatively little obstruction to 
the development of fibrous root; and it is in these classes of soil 
that the special efficiency of phosphoric acid in superphosphate 
and basic slag has been most observable. 
We believe that successful bulb formation, whether of kitchen ■ 
vegetables or of garden flowers, is best accomplished not by 
increasing the £.bove*-ground organs, of collection (the leaves), 
but by encouraging the underground fibrous roots. 
Fruit Crops. 
Passing on to flowering plants and fruit trees, it is found 
that these, though differing materially ini their individual cha¬ 
racteristics', as well as in their time and period of growth, yet 
they each require phosphoric acid and potash as their domi¬ 
nant constituents when blooming and developing seeds or fruits. 
Further, fruit differs from most other crops in that a longer 
season of ju'eparation is required, in which the growth may be 
so' directed as. to prepare the plant or tree for the proper 
development of fruit-buds, a.s distinct from seed, or succulence 
in the vegetable crops. 
Fruit differs in. its characteristics from the ordinary garden 
crops in that its growth and development require a little dif¬ 
ferent treatment, since it is necessary that there should be a. 
constant transfer of nitrogen from the tree to the fruit through¬ 
out the entire growing season. The growth of each succeeding 
year of tree and fruit is dependent, not altogether upon the 
food acquired during-the year, but as well upon that acquired 
in the previous year, and which has been stored up in bud 
and branches. - 
Market Garden Crops 
Another group, of crops is distinguished as a class, not so 
much because of their peculiar habits of growth as because 
of the objects of their growth, though 'this latter fact has a 
very important bearing upon economical methods of manurin°\ 
This class of plant® includes, what are called “ market-garden 
crops,’’ as Cabbage, Lettuces, Beet, Asparagus, Turnips, Cu¬ 
cumbers, Celery, Peas, Beans, Radishes, Onions, Carrots, Broc¬ 
coli, and various others. The particular object in raising 
these is to secure rapidity in growth, and thus to-ensure high 
quality, which is measured by the element of succulence. 
In order that this may be accomplished they must be sup¬ 
plied with an abundance of available plant-food, and, since 
nitrogen is the one element which more than any other en¬ 
courages and stimulates leaf and stem growth, its use is espe¬ 
cially beneficial to all these crops. They must not lack for 
this element in any period of their growth, though, of course, 
a sufficiency of minerals must be available in order that the 
nitrogen may be properly utilised. 
Farmyard manure, or sea-weed, where it can be obtained, 
is frequently applied in. enormous quantities every year, or 
every second year for the growth of market-garden crops. 
The manure used supplies nitrogen, phosphoric acid, potash, 
and other ingredients of plant-food far in excess of the amount 
removed in the crop. And yet it is found necessary to furnish 
this heavy dressing of manure. If this is not done the crop 
is poor and unprofitable. This is found more especially to be 
the case in the production of early crops, or those grown “ out 
of season.” It is found necessary to use enormous quantities 
of manure for these crops—far in excess of the plant-food re- 
moved in the crop. 
Gardeners who make a speciality of growing large areas of 
early Cabbage or Cauliflowers find it almost impossible to 
make the land rich enough the first year. They find that the 
second or third crop, grown and manured every year on the 
same land, is better and earlier than the first crop. To give 
an illustration of this from the Rothamsted experiments, we. 
may quote the following:—In 1876 a field of exhausted land 
was taken and laid out. for the continuous growth of Potato® 
on ten plots. One of these was left entirely without manure, 
while another received 14 tons per acre of farmyard dung. In 
the first year the dung gave an. increase over the unmanured 
plot of 8 cwt. of tubers per acre only. In the second year’s 
application of dung a gain of 2 tons 17-|- cwt. of Potato® was 
obtained, in the third year a similar quantity, and in, the 
fifth year the 14 tons of dung gave an increase of 4 tons 3 cwt, 
of tubers over the unmanured. Thus, for the production of 
good garden crop® additional manure is constantly applied. 
There is no difference between the manorial requirements 
of an early and a fate crop of vegetables. Both require the 
same food, and the late crop, which is frequently larger, re¬ 
quires more rather than less food or manure per acre. And 
yet in practice it is found absolutely necessary to use far more 
manure for the early crop- than for the late crop. 
The explanation is this: All our farm and garden plants 
take up this nitrogen in the form of nitric acid or nitrate. At 
one time it was supposed that the plants took up their nitrogen 
in the form of ammonia. It is now known that the ammonia 
must be con,verted into nitric acid. No matter how much 
nitrogen the soil or the manure may contain, it becomes avail¬ 
able for plant food only after it is converted into nitric acid. 
Therefore so long asi the gardener applies his nitrogen, in the 
form of farmyard manure or seaweed, it is absolutely necessary 
to use enormous quantities. They find it profitable to use it, 
but, thanks to the investigations of scientific men, we now 
know how to obtain the same result with far greater certainty 
and at vastly less cost. 
(To be continued .) 
Mr. R. W. Smith, gardener to Mr. H. Tunstall, of Regyfnrd, 
has won the Challenge Shield in connection with the Nelson 
Horticultural Show, 
