I came across an online source of old time advice , and here are some tips from the past:
Flower Gardening.
Autumn is the best time to manure a flower garden. It should be done once a year, and better in spring (April) than not at all. Lay on four inches deep of well-rotted manure, and dig it in at once. During the summer the earth will need now and then to be stirred with a hoe or rake; but in May it should always be thoroughly dug over with a spade, avoiding of course the plants in the bed. In May transplanting, setting of bulbs, or bedding plants and sowing seeds may be done.
Weeding can be best done by hand, early in the morning; letting the sun kill the weeds that are pulled up.
Never water unless the soil evidently requires it. Clayey soils seldom need it, loose and sandy more often. Use always a watering-pot, with a rose, to sprinkle gently, without pouring or dashing. Rain-water is the best; it may be collected in a hogshead from a roof-spout. Very cold water should never be used for flowers, better too warm than too cold.
Shade-trees spoil a garden, but it should be protected from a strong wind.
PRACTICAL DIRECTIONS FOR GARDENERS.
1. Perform every operation in the proper season.
2. Perform every operation in the proper manner.
This is to be acquired in part by practice, and partly also by reflection. For example, in digging over a piece of ground, it is a common practice with slovens to throw the weeds and stones on the dug ground, or on the adjoining alley or walk, with the intention of gathering them off afterwards. A better way is to have a wheel-barrow or a large basket, in which to put the weeds and extraneous matters, as they are picked out of the ground. Some persons, in planting or weeding, whether in the open air, or in hot-houses, throw down all seeds, stones, and extraneous matters on the paths or alleys, with a view to pick them up, or sweep or rake them together afterwards, it is better to carry a basket or other utensil, either common or subdivided, in which to hold in one part the plants to be planted, in another the extraneous matters, etc.
3. Complete every part of an operation as you proceed.
4. Finish one job before beginning another.
5. In leaving off working at any job, leave the work and tools in an orderly manner.
6. In leaving off work for the day, make a temporary finish, and carry the tools to the tool house.
7. In passing to and from the work, or on any occasion, through any part of what is considered under the charge of the gardener, keep a vigilant look out for weeds, decayed leaves, or any other deformity, and remove them.
8. In gathering a crop, remove at the same time the roots, leaves, stems, or whatever else is of no farther use, or may appear slovenly, decaying, or offensive.
9. Let no crop of fruit or herbaceous vegetables go to waste on the spot.
10. Cut down the flower-stalks on all plants.
11. Keep every part of what is under your care perfect in its kind.
Attend in spring and autumn to walls and buildings, and get them repaired, jointed, glazed, and painted where wanted. Attend at all times to machines, implements, and tools, keeping them clean, sharp, and in perfect repair. See particularly that they are placed in their proper situations in the tool-house. House every implement, utensil, or machine not in use, both in winter and summer. Allow no blanks in edgings, rows, single specimens, drills, beds, and even, where practicable, in broadcast sown pieces. Keep edgings and edges cut to the utmost nicety. Keep the shapes of the wall trees filled with wood according to their kind, and let their training be in the first style of perfection. Keep all walks in perfect form, whether raised or flat, free from weeds, dry, and well rolled. Keep all the lawns, by every means in your power, of a close texture, and dark green velvet appearance. Keep water clear and free from weeds, and let not ponds, lakes, or artificial rivers, rise to the brim in winter, nor sink very far under it in summer.
For lots more, see the HORTICULTURE area of the Household Cyclopedia.