Seed delivery to site is a critical step in seed‐based restoration programs. Months or years of seed collection, conditioning, storage, and cultivation can be wasted if seeding operations are not carefully planned, well executed, and draw upon best available knowledge and experience. Although diverse restoration scenarios present different challenges and require different approaches, there are common elements that apply to most ecosystems and regions. A seeding plan sets the timeline and details all operations from site treatments through seed delivery and subsequent monitoring. The plan draws on site evaluation data (e.g. topography, hydrology, climate, soil types, weed pressure, reference site characteristics), the ecology and biology of the seed mix components (e.g. germination requirements, seed morphology) and seed quality information (e.g. seed purity, viability, and dormancy). Plan elements include: (1) Site treatments and seedbed preparation to remove undesirable vegetation, including sources in the soil seed bank; change hydrology and soil properties (e.g. stability, water holding capacity, nutrient status); and create favorable conditions for seed germination and establishment. (2) Seeding requirements to prepare seeds for sowing and determine appropriate seeding dates and rates. (3) Seed delivery techniques and equipment for precision seed delivery, including placement of seeds in germination‐promotive microsites at the optimal season for germination and establishment. (4) A monitoring program and adaptive management to document initial emergence, seedling establishment, and plant community development and conduct additional sowing or adaptive management interventions, if warranted. (5) Communication of results to inform future seeding decisions and share knowledge for seed‐based ecological restoration.

Summary: 1. Highly disturbed areas such as surface‐mined land provide a great challenge for ecological restoration. The goal is to identify appropriate restoration approaches in a continuum between technical reclamation and spontaneous succession. In particular, on slopes endangered by erosion, appropriate methods are needed that quickly establish vegetation cover but also take into account the natural potentials of the site.2. In the mined area Roßbach (Saxony‐Anhalt, Germany), we evaluated the effects of spontaneous succession and assisted site recovery (species introduction through hay transfer and sowing) during a 9‐year experiment. We asked how rates and pathways of vegetation development differ between treatments and whether species composition converges over time owing to species exchange.3. The application of green hay as well as the sowing of regional seed mixtures clearly accelerated vegetation development and led to the rapid establishment of species‐rich grasslands. Hay transfer was most successful owing to the high amount of transferable target species. Moreover, both treatments facilitated the establishment of cryptogams and provided effective erosion control. Also, hay transfer and sowing clearly affected the pathway of succession.Calamagrostis epigejosmigrated from nearby source populations and became increasingly dominant at sites with spontaneous succession. In contrast, the species‐rich grasslands established after hay transfer and sowing were highly resistant to invasion ofCalamagrostisand other ruderals.4. Species exchange between treatments led to increasing similarity in vegetation composition over time. Nine years after implementation of the experiment, we did not find any significant differences between treatments in terms of total vegetation cover, species richness and the number of target species. However, the dominance ratio between target and nontarget species differed significantly. Species introduction through hay transfer and sowing led to a permanently higher abundance of grassland species and a lower coverage of ruderals compared with spontaneously developed sites. Hence, our results highlight the importance of initial floristic composition and the order of species arrivals for long‐term vegetation development.5. Synthesis and applications. Hay transfer and sowing of regional seed mixtures are appropriate restoration tools to achieve rapid revegetation when no potential seed sources of target species are available nearby or there are undesirable species that need to be suppressed. Our results show that introduced grassland species are able to grow under postmining site conditions and can migrate into adjacent spontaneously developing sites. A combination of spontaneous and assisted site recovery can promote the development of species‐rich grasslands in postmining landscapes.