Agriculture was the main contributor to Maidstone's prosperity over the centuries. The town became the market centre for a fertile hinterland in which cereals were grown and animals reared. From the thirteenth century onwards the October fair was the focus for livestock, and by the late sixteenth century Maidstone was the second largest grain market in Kent.
The trade in Kentish ragstone continued throughout the medieval period. The stone was used for substantial buildings in the town itself, and was also used in, for instance, the Tower of London and Hampton Court; Rochester cathedral, castle, town walls and bridge were all built of Kentish rag. In 1348 it was shipped to London to build Queen Philippa's great wardrobe in Cheapside, and in the fifteenth century the gates of the city of Canterbury were repaired with Maidstone rags. During the wars with France, the fortifications of Calais were built of it, and in 1418 it was used to make 7,000 cannon balls.
Although weaving had been practised in Maidstone from at least the early thirteenth century, it was on a small scale and did not expand until after 1331 when Edward III invited continental clothiers to settle in England and set up industrial weaving. It was not until the post-medieval period, however, that weaving and also thread twisting became well established in Maidstone.
The commercial development of Maidstone arose largely because of the river Medway. As the river was not navigable upstream of Maidstone until the mid-eighteenth century, the town became the northern port for the Weald, through which raw materials such as timber, iron and ragstone were shipped to London and elsewhere. The port was probably sending out ragstone to London in the Romano-British period, and the same trade continued throughout the medieval period, with other goods being brought back in return. Its position as a shipping centre ensured that during the wars with France, Maidstone was always on the list of ports where vessels of more than 40 or 50 tons capacity could be commandeered.
By the 1590s grain was being increasingly exported, particularly to London, and other crops, such as flax, were grown to a lesser extent and for local use in thread twisting. During the seventeenth century, Kent between Maidstone and Ashford began to specialise in fruit and hops, with many hop gardens along the sandstone ridge between the two towns. Hop picking became a significant element in seasonal employment.
The expansion of agriculture continued in the eighteenth and nineteenth centuries, with Kentish cherries and apples being especially sought after in London, and wheat still in demand. Barley was grown for the Maidstone breweries, the hop gardens increased for the same market and for selling further afield. Filberts (cob nuts) were cultivated on a commercial scale. Kentish bullocks were said to be the largest breed in England.
By the 1880s, Maidstone's residential area was expanding so that there was less agricultural land in the vicinity, but even so, the remaining land continued to be agriculturally productive, particularly for fruit and hops. Although hop growing had declined, fruit was still an important crop at the end of the twentieth century.
Ragstone from the Maidstone area was sent to London throughout the sixteenth and seventeenth centuries, some being used in rebuilding St Paul's cathedral. It was also used for paving stones and public buildings in Maidstone itself. Ragstone is still quarried in the district, mainly for use in the manufacture of tar macadam.
Many fulling mills, using the fuller's earth found at Boxley and Leeds near Maidstone, were built on the rivers Len and Medway in the late sixteenth century. For instance, there were thirteen fulling mills and one corn mill between Maidstone and East Farleigh in the 1570s, but they had become very rare by the end of the eighteenth century as local cloth manufacture declined, and the last fulling mill closed c. 1820.
In 1567 c. 60 families of refugees from the Low Countries settled in Maidstone to help revitalise the town's cloth production and increase its variety. More families arrived in 1573, and by 1585 about 120 Dutch adults lived and worked in the town, passing on their skills to English apprentices. By the early seventeenth century the trade had been taken over by the local inhabitants, but, although cloth manufacturing continued for some 200 years, the making of woollen cloth soon died out.
Dutch immigrants introduced thread twisting (Dutch work) to Maidstone during the 1560s, and by the seventeenth century Maidstone had become the centre for linen-thread production. The thread was made from flax, most of which was locally grown and retted. It was spun and then passed to the craftsmen who twisted it; after that it was dyed. It was a labour-intensive activity, and in 1664 it was said that 8,000 people in Maidstone were employed in thread twisting.
Maidstone thread was widely exported during the seventeenth century but by 1680 competition from the West Country, where both raw materials and labour were much cheaper, led to a decline in demand for the more expensive Maidstone product. Coarse thread was produced for another hundred years, but by the end of the eighteenth century even that demand declined, and by the 1831 census, only 88 townsmen were employed in making hop-bags, ropes and blankets.
The earliest paper mill in Kent was established at Dartford at the end of the sixteenth century, and by the mid-seventeenth century mills had proliferated in the Medway valley close to Maidstone, with seven functioning between 1671 and 1700. At that time the mills in the Maidstone area were producing great quantities of paper and pasteboard, much of it being shipped to London whence rags were brought as raw material. By 1733 there were fourteen mills; by 1800 there were nineteen, and by 1865 there were double that number, each employing an average of 240 people.
Turkey mill, first mentioned as a fulling mill on the river Len in 1629, was converted into a paper mill before 1680. Two other fulling mills on the Len were converted to paper making in 1719, one producing white and one producing brown paper, but in 1739 they were demolished and a new Turkey Mill complex built on a more ambitious scale. A beam engine was installed in c.1807, and the mill then became one of the largest mills in the country, with 263 women, 62 men, 26 girls and 24 boys, employed in 1865. It closed in 1976.
The Lower Tovil mills were converted from fulling to paper making by 1686: Destroyed by fire in 1814 and 1889, they were quickly rebuilt and closed in the early 1960s. Upper Tovil mill, first recorded c. 1650, was converted to a paper mill by 1680. It burnt down c.1860 but was subsequently to be rebuilt as the first of the Reed paper mills (now Reed International).
Several other mills survive. For example, Hayle mill produces hand-made paper and Springfield mill also makes specialized papers.
In 1566 Maidstone had four landing places (one of which was at the bottom of St Faith's Street and later known as Towne Wharf), and five ships and hoys of between 30 and 50 tons. They must have been used for shipping the local products of ragstone, fuller's earth and timber. The town charter of 1619 empowered the corporation to charge tolls for wharfage, anchorage, and groundage of all vessels berthing at Maidstone, and in 1628 and 1644 parliamentary acts were passed to improve the navigation of the Medway, including the construction of locks and towpaths and deepening the river by dredging. River trade in iron ordnance, canon balls, timber, wood, corn, stone, hay, hops, wool, and leather was expanding greatly, and in 1740 the Lower Medway Navigation Company was formed to deal with and maintain the improvements to the river, which was then made navigable as far inland as Forest Row, Sussex. A tidal lock built at Allington in 1792 further improved navigation.
Maidstone also became a centre for barge building, and by 1809 c. 25 barges were trading from Maidstone. Larger vessels travelled to the north of England, France and Holland carrying stone, coal and general goods. The Strood to Gravesend canal, which opened in 1824, reduced the waterborne route from Maidstone to London by c. 40km, and the number of vessels using the port increased, so that by 1834 Maidstone had more than 50 vessels of 20-90 tons. Although the canal closed in the 1840s because of competition from railways, shipping continued to grow, and by 1880 Maidstone boasted 60 vessels, with some of 150 tons occasionally berthing there. By World War I, however, competition from the improved road network and railways led to Maidstone's decline as a port, and today little commercial shipping comes as far as the town
The first brewery in Maidstone was the Lower Brewery, opened in Stone Street in the mid-seventeenth century; the Upper Brewery in Brewer Street began at much the same time. By 1700 they were jointly owned, but after changes in ownership the Upper Brewery was demolished c.1820 while the Lower Brewery continued in business until 1930, when it amalgamated with Fremlin's Brewery and the land was sold. There were four other small breweries in the late seventeenth century, and in the late eighteenth century the Heathorn Brewery opened in Earl Street, but was virtually derelict when Ralph Fremlin bought it in 1831. After becoming a public company in 1925 it amalgamated with Whitbread's, to form the Whitbread Fremlin Group. The Medway Brewery in St Peter Street, founded in 1799, flourished until 1894 when it suffered a serious fire. After being rebuilt and modernised, it merged with E. Winch of Chatham in 1899, to become the Style and Winch Brewery. Success throughout the first half of the twentieth century led to a take-over by the brewing giants Courage and Barclay. Finally, Mason and Co was established in the early 1840s but remained a small family business throughout its existence. In the early eighteenth century, cider was brewed commercially, from a mixture of the local apple varieties. The Victorian taste for mineral waters led to there being nine ginger beer and soda water manufacturers in 1872, and they were still manufacturing in the 1930s.
There have been at least three distilleries in Maidstone in the post-medieval period. One stood in Stone Street from the mid-seventeenth century until at least the 1730s. A distillery for Maidstone Geneva was founded on the south side of Bank Street in 1789, and although its product was much sought after, it fell out of use after the death of its founder c.1819. In 1853, Grant's Morella Cherry Brandy distillery was established in Hart Street and by 1892 the firm owned another distillery and an orchard of 20,000 cherry trees at Lenham. Grant's survived until the mid-twentieth century.