A solid plant growth regulant composition comprises a solid water-insoluble resinous carrier which is thermoplastic or solvent-soluble, in intimate contact with at least one plant growth regulant which preferably constitutes 5-95% by weight of the mixture of plant growth regulant and resinous carrier. The composition may also include one or more pesticides, e.g. insecticide especially a nematocide, a viricide or soil fungicide. There may also be included wood flour, carbon black and mineral fillers such as talc, clays, silica and synthetic calcium and magnesium silicates. Examples are given of many plant growth regulants falling in the following classes of compounds:- (a) indolyl acetic acid and arylalkansic acids, (b) aryloxyalkausic acids, (c) the salts and esters of acids in (a) and (b), (d) esters of phenoxyalkanols, (e) chlorinated alkansic acids, (f) a -chloroacetamides, (g) carbamates, (h) dithiocarbamates, (i) substituted ureas, (j) N-naphthylphthalamic acid and its alkali metal salts and N-1-naphthylphthalamide, (k) maleic hydroxide, (l) triazine and triazole derivatives, (m) substituted benzoic acids, (n) benzonitriles having at least one substituent in the ortho position selected from halogen, hydroxyl, amino, alkylamino, alkyl and alkoxy, (o) miscellaneous plant growth regulants, e.g. octachlorocyclohexenone; pp-dibutyl-N,N-diisopropyl phosphinamide; 3-5 dimethyl tetrahydro-1:3:5:2H-thiadiazine-2-thione; quaternary ammonium salt prepared from 2:21 dipyridyl and ethylene dibromidogibberellic acid; (p) mixtures of plant growth regulants, e.g. (i) mixtures of 2 chlorobenzoic acid selected from 2:3:6 trichloro-, 2:3:5:6-tetrachloro- and 2:6 dichloro benzric acid, salt or ester; (ii) mixtures of a 2:2 dichloropropionic acid, salt or ester and an asymmetric phenyl urea such as 3-(p-chlorophenyl)-1:1-dimethyl urea; (iii) mixtures of 3-amino-1:2:4 triazole and another herbicide such as an aryloxy alkanoic acid, 2:2 dichloro or 2:2:3 trichloro propionic acid, an asymmetric substituted phenylurea as 3-(p-chlorophenyl)1:1 dimethyl urea; a substituted benzoic acid or substituted benzonitrile. Specified resinous carriers are of naturally occurring resins such as colophony, wood resins, copal, dammar and kauri gum. Specified synthetic resins are of solvent-soluble or fusible phenol aldehyde resins particularly the phenol formaldehyde resins, alkyd resins such as those derived by condensing maleic anhydride and resin, glycerylphthalate resins, penta-erythrityl resins, oxidized resins, coumarone and coumarone-indene resins, solid polychlorinated polyphenyls such as "Aroclor" (Registered Trade Mark), polyethylene, chlorinated rubber, polyvinyl-chloride and acrylate and methacrylate resins. Other resinous carriers are asphaltic bitumens, petroleum and coal tar pitches and naturally occurring asphaltites. The compositions may be extruded into pellets or formed into rods, sheets, blocks and the like or coated on to solid supports for example wood or metal. Specification 828,871 is referred to.ALSO:A solid plant growth regulant composition comprises a solid water-insoluble resinous carrier which is thermoplastic or solvent-soluble, in intimate contact with at least one plant growth regulant which preferably constitutes 5-95% by weight of the mixture of plant growth regulant and resinous carrier. The composition may also include one or more pesticides, e.g. insecticide especially a nematocide, a vircide or soil fungicide. There may also be included wood flour, carbon black and mineral fillers such as talc, clays, silica and synthetic calcium and magnesium silicates. Examples are given of many plant growth regulants falling in the following classes of compounds:- (a) Indolyl acetic acid and arylalkanoic acids, (b) aryloxyalkanoic acids, (c) the salts and esters of acids in (a) and (b), (d) esters of phenoxyalkanols, (e) chlorinated alkansic acids, (f) a -chloroacetamides, (g) carbamates, (h) dithiocarbamates, (i) substituted ureas, (j) N-1-naphthylphthalamic acid and its alkali metal salts and N-1-naphthylphthalimide, (k) maleic hydroxide, (l) triazine and triazole derivatives, (m) substituted benzoic acids, (n) benzonitriles having at least one substituent in the ortho position selected from halogen, hydroxyl, amino, alkylamino, alkyl and alkoxy, (o) miscellaneous plant growth regulants, e.g. octachlorocyclohexenone; pp-dibutyl-N,N-diisopropyl phosphinamide; 3-5 dimethyl tetrahydro-1:3:5:2H-thiadiazine-2-thione; quaternary ammonium salt prepared from 2:21 dipyridyl and ethylene dibromidogibberellic acid; (p) mixtures of plant growth regulants, e.g. (i) mixtures of 2 chlorobenzoic acid selected from 2:3:6 trichloro-, 2:3:5:6-tetrachloro- and 2:6 dichloro benzric acid, salt or ester; (ii) mixtures of a 2:2 dichloropropionic acid, salt or ester and an asymmetric phenyl urea such as 3-(p-chlorophenyl)-1:1-dimethyl urea; (iii) mixtures of 3-amino-1:2:4 triazole and another herbicide such as an aryloxy alkanoic acid, 2:2 dichloro or 2:2:3 trichloro propionic acid, an asymmetric substituted phenylurea as 3-(p-chlorophenyl)-1:1 dimethyl urea; a substituted benzoic acid or substituted benzonitrile. Specified resinous carriers are of naturally occurring resins such as colophony, wood resins, copal, dammar and kauri gum. Specified synthetic resins are of solvent-soluble or fusible phenol aldehyde resins particularly the phenol formaldehyde resins, alkyd resins such as those derived by condensing maleic anhydride and rosin, glycerylphthalate resins, penta-erythrityl resins, oxidized resins, coumarone and coumaroneindene resins, solid polychlorinated polyphenyls such as "Aroclor" (Registered Trade Mark), polyethylene, chlorinated rubber, polyvinylchloride and acrylate and methacrylate resins. Other resinous carriers are asphaltic bitumens, petroleum and coal tar pitches and naturally occurring asphaltites. The compositions may be extruded into pellets or formed into rods, sheets, blocks and the like on to solid supports for example with a metal. Specification 828,871 is referred to.ALSO:A solid plant growth regulant composition comprises a solid water-insoluble resinous carrier which is thermoplastic or solvent-soluble, in intimate contact with at least one plant growth regulant which preferably constitutes 5-95% by weight of the mixture of plant growth regulant and resinous carrier. The composition may also include one or more pesticides, e.g. insecticide especially a nematocide, a viricide or soil fungicide. There may also be included wood flour, carbon black and mineral fillers such as talc, clays, silica and synthetic calcium and magnesium silicates. Examples are given of many plant growth regulants falling in the following classes of compounds: (a) Indolyl acetic acid and arylalkanoic acids; (b) aryloxy-alkanoic acids; (c) the salts and esters of acids in (a) and (b); (d) esters of phenoxyalkanols; (e) chlorinated alkanoic acids; (f) a -chloroacetamides; (g) carbamates; (h) dithiocarbamates; (i) substituted ureas; (j) N-1-naphthylphthalamic acid and its alkali metal salts and N-1-naphthylphthalimide; (k) maleic hydroxide; (l) triazine and triazole derivatives; (m) substituted benzoic acids; (n) benzonitriles having at least one substituent in the ortho position selected from halogen, hydroxyl, amino, alkylamino, alkyl and alkoxy; (o) miscellaneous plant growth regulants e.g. octachlorocyclohexenone; pp-dibutyl-N,N-diisopropyl phosphinamide; 3-5 dimethyl tetrahydro - 1 : 3 : 5 : 2H - thiadiazine - 2 - thione; quaternary ammonium salt prepared from 2 : 21-dipyridyl and ethylene dibromidogibberellic acid; (p) mixtures of plant growth regulants e.g. (i) mixtures of 2-chlorobenzoic acid selected from 2 : 3 : 6 - trichloro -, 2 : 3 : 5 : 6 - tetrachloro - a - 2 : 6 - dichloro benzoic acid, salt or ester; (ii) mixtures of a 2:2-dichloropropionic acid, salt or ester and an asymmetric phenyl urea such as 3-(p-chlorophenyl)-1: 1-dimethyl urea; (iii) mixtures of 3-amino-1 : 2 : 4-triazole and another herbicide such as an aryloxy alkanoic acid, 2 : 2-dichloro or 2 : 2 : 3-trichloro propionic acid, an asymmetric substituted phenylurea as 3-(p-chlorophenyl)-1 : 1-dimethyl urea; a substituted benzoic acid or substituted benzonitrile. Specified resinous carriers are of naturally occurring resins such as colophony, wood rosins, copal, dammar and kauri gum. Specified synthetic resins are of solvent-soluble or fusible phenol aldehyde resins particularly the phenol formaldehyde resins, alkyd resins such as those derived by condensing maleic anhydride and rosin, glycerylphthalate resins, penta-erythrityl resins, oxidized rosins, coumarone and coumarone-indene resins, solid polychlorinated polyphenyls such as "Aroclor" (Registered Trade Mark), polyethylene, chlorinated rubber polyvinylchloride and acrylate and methacrylate resins. Other resinous carriers are asphaltic bitumens, petroleum and coal tar pitches and naturally occurring asphaltites. The compositions may be extruded into pellets or formed into rods, sheets, blocks and the like on to solid supports for example with a metal. Specification 828,871 is referred to.