Grah mahunar (Phaseolus vulgaris L.) kultura je koja se uzgaja u prehrambene svrhe u mnogim dijelovima svijeta i mnogim klimatskim zonama, zahvaljujući svojoj prilagodljivosti na pedološke i klimatološke čimbenike, te kratkoj vegetaciji. Kopriva (Urtica dioica L.) je kozmopolitska vrsta koja raste kao korov na zapuštenim zemljištima uz naselja. Poznata je po svojoj prehrambenoj vrijednosti i ljekovitosti. U poljoprivredi se tradicijski koriste insekticidna svojstva nekih njenih pripravaka, a od nje se rade i gnojiva. O koristi koprive prenosi se usmenim putem, a temeljeno na iskustvu, ali bez konkretnih dokaza. Cilj ovog rada je istražiti utjecaj pripravaka kratke (24 sata) i duge (14 dana) maceracije koprive u vodi na vegetativni porast biljaka graha mahunara. Svrha rada je utvrditi promjene u vegetativnom porastu graha mahunara ovisno o vrsti pripravka koprive (kratka i duga maceracija) i učestalosti primjena tih pripravaka (jedan, dva ili tri puta) radi davanja preporuke za njihovu primjenu. Rezultati istraživanja su dobiveni iz poljskog pokusa postavljenog u dvije repeticije po osam gredica od kojih je svaka bila tretirana na različit način. Tri gredice tretirane su folijarno pripravkom kratkog macerata (jedan, dva ili tri puta), tri gredice zalijevanjem tla pripravkom dugog macerata (jedan, dva ili tri puta), jedna gredica nije bila tretirana (kontrola), a jedna je tretirana folijarno gnojivom UREA. Gredice tretirane više puta tijekom vegetacije, tretirane su u razmacima od sedam dana. Biljke su uzorkovane 7 dana nakon tretiranja, te im je mjerena visina, promjer stabljike, broj listova, masa suhe stabljike i lista, te lisna površina. U svim mjerenim parametrima pripravci koprive su pokazali povoljno djelovanje na vegetativni porast biljaka u usporedbi s kontrolnom gredicom. U tri parametra (masa suhe stabljike, broj i masa suhog lista) najveća je vrijednost zabilježena na gredici tretiranoj dva puta dugim maceratom koprive. U dva parametra (promjer stabljike i lisna površina) na gredici tretiranoj Ureom, a u jednom parametru (visina stabljike) na gredici tretiranoj jednom kratkim maceratom koprive.

Common bean (Phaseolus vulgaris L.) is a crop culture grown for nutritional purposes worldwide in diferent climate regions, due to its adaptibility to pedological and climatological factors, as well as its short vegetative cycle. Stinging nettle (Urtica dioica L.) is a cosmopolitan, ruderal weed that grows near human settlements. It is known for its nutritional value and health benefits. In agriculture it is traditionaly used for its insecticidal properties, as well as being made into organic plant manure. The benefit of these nettle preparations is forwarded based on experience, but with no actual evidence to show. The aim of this paper is to explore the effects of short (24 hours) and long (14 days) aquaeous extract of stinging nettle on vegetative growth of common bean plants. The purpose of this paper is to establish the differences in vegetative growth of common beans depending on the use of either short or long aquaeous extract of stinging nettle, as well as the frequency of application (one, two or three times) of both, in order to give recommendations for their use. The results were collected in a field experiment set up in two repetitions of eight beds, which have all been treated differently. Three beds had a foliar treatment with short aquaeous extract (one, two or three times), three beds were watered with long aquaeous extract (one, two or three times), one bed was not treated at all (control bed) and one had a foliar treatment with UREA. The beds that recieved more than one treatment have been treated every seven days. Plants have been sampled seven days after being treated, and measured for their height, stem width, leaf number, dry stem and leaf weight and leaf area. In all measured parameters aquaeous extracts of stinging nettle have shown a favorable effect on the vegetative growth of plants as compared to the control bed. Results show that in three parameters (dry stem weight, leaf number and dry leaf weight) the highest value was recorded on beds treated twice with long aquaeous extract of stinging nettle, in two parameters (stem width and leaf area) on beds treated with UREA and in one parameter (stem height) on beds treated once with short aquaeous extract of stinging nettle.