Although one would expect species to develop and maintain themselves through self- seeding—when after a few years a sufficient seed reserve has been built up in the soil— practice shows us that one will need to sow additional seeds every year. On moist soils, some of the species in the composition one has sown turn out to start dominating through self-seeding. Other, less vigorous species will, as a result, decrease in numbers and may disappear completely. In this manner, one may, in the end, be left with only a few or even just one or two species. This is the case on highly fertile cultivated soils where, for instance, Papaver rhoeas and Matricaria maritima may gain the upper hand at the detriment of other species.
The more the soil type matches the type on which the species thrive under natural circumstances, the better the results of self-seeding. Generally, this is not the case. It is therefore preferable to apply additional sowings each year. One may reduce the quantity of seed sown initially, 0.5 g/m2 will usually suffice. In addition, one may try to intervene in such a way that the desired species persist. After sowing, basically no maintenance is necessary until after flowering. Yet it may be wise to weed out obnoxious unwanted species as long as one can do so without visibly disturbing the vegetation. Aesthetically speaking, the results will be greatly improved. After the main flowering period is over, the flower field is mown. On soils susceptible to weed invasions, one should not wait with mowing until the last flower has faded, for one really needs to start battling the unwanted species in time. If one prefers to do so, one may leave the mown-off plants for a number of days, thus allowing the seeds to ripen and fall out. After carrying off the hay, the soil is worked over at a shallow depth, which is called ‘stubbling’ (working on the stubble, i. e. the remaining parts of the stem base), with the aid of hoe, onion hoe, hand cultivator or disk harrow, depending on the size of the plot. This technique is very important in battling the unwanted species; they are removed and do not get a chance for re-growth. It must be repeated as often as the plot starts ‘greening’. One keeps repeating this until the plot is sown again. Obviously, during these activities and during the soil cultivation prior to sowing, one cannot avoid removing the seedlings of the desired species as well, unfortunate as it may be.
Maintenance generally mirrors traditional agricultural techniques; ploughing, harrowing, sowing, harrowing in and rolling the field in autumn or spring. On smaller plots, ploughing becomes digging, harrowing becomes raking, etcetera. All of the aforementioned activities are repeated each year.
Older flower fields may suffer from the development of noxious perennial weeds such as Equisetum arvense. Cultivation (i. e. removing their rhizomes completely) may be possible in small-scale situations. In larger plots, a year of letting it lie fallow, combined with repeated mechanical activity (hoeing, harrowing) may give good results. Biological measures, such as crop rotation with higher and denser crops over a period of some years, for example with Phacelia, may be effective as well. But as a rule, older flower fields are rather difficult to keep free from unwanted weeds, giving them a disturbed and less free – flowering aspect. Incidentally, one may prevent situations of too low soil fertility by spreading a bit of old manure or fresh soil.
