Buddhist ethics & hydroponics: ethical issues?

AFAIK, in Theravada, ordained monastics are prohibited from growing their own food. Even hydroponics would likely be prohibited by vināya due to probability of harming small unseen life (algae, etc) in maintaining a hydroponic system. Are there any ethical concerns for Buddhist laity, including those moving towards but not yet fully ordained, especially from a Theravada perspective? As a side issue do ordained monastics maintain houseplants or gardens, or outsource this work to laity?