In the immediate vicinity of the metropolis are estimated to comprise above 10,000 acres, about 2,000 of which are wholly cultivated by the spade and partly by the plough: not more than one-fourth, however, of this quantity is situated in Middlesex, the rest is in the counties of Surrey, Kent, and Essex. Soon after Christmas, when the weather is open, they begin by sowing the borders, and then the quarters with radishes, spinach, onions, and all other seed-crops. As soon afterwards as the season will permit, which is generally in February, the same ground is planted with cauliflowers from the frames, as thick as if no other crop then had possession of the ground. The radishes, &c., are soon sent to market, and when the cauliflowers are so far advanced as to be earthed up, sugar-loaf cabbages are planted from the aforesaid seed-crops; when these are marketed, the stalks are taken up, the ground cleared, and planted with endive and celery from the said seed-crops: and daily as these crops are sent to market, the same ground is cropped with celery for winter use. The average produce of these gardens is supposed to amount to 200l. annually per acre, the profit of which is calculated to be very great in successful seasons. The annual produce of all the garden-ground cultivated to supply the London markets is estimated by Mr. Middleton at 645,000l., which, with 400,000l. produced by the fruit gardens, makes a total of 1,045,000l. for the consumption of the metropolis and its environs, in fruits and vegetables only.
Source: Leigh's New Picture of London. Printed for Samuel Leigh, 18, Strand;
by W. Clowes, Northumberland Court. 1819