Frederick Countty Office 330 Montevue L Lane Frederick, Maryyland 21702 TEL 301-600-15594 FAX 301-600-1588 www.frederick.uumd.edu Growing Waterm melon Connie Holland, H Adaams County Master Garddener One of the joys of o my summ mer garden iss growing an nd eating wattermelons. M My love of w watermelons comes from m spennding summeers on my grrandfather’s farm where he raised theem for us to enjoy. Nothhing was bettter than sittinng under the farm’s hugee trees eating g cool waterm melon drippping with sw weet juices. I have grownn wateermelons for the years with w great succcess, harvessting over 5000 lbs. from three hills thhe last two yyears when, just ffor fun, I staarted weighin ng each wateermelon. Wateermelons oriiginated in Africa. A Therre are over 50 00 varieties.. Watermeloons come in tthree main seed groups: earlyy season, maain season an nd seedless. Early season n watermelonns mature inn 70-75 dayss and producce the smalller sized fru uit, often callled "ice box"" melons sin nce they readdily fit on a rrefrigerator sshelf. 1 poundds and usuallyy have dark green rinds.. The type I Mainn season melons producee in 80-85 daays, weigh 18-30 like tto grow is Sangria. It geets really larg ge; my biggeest so far weeighed 36 poounds. Their taste is veryy sweet and crispp, readily oveercoming the fact that th hey contain seeds. s Seedeed main season watermellons also com me in yellow w or orrange-fleshed varieties such as Desert King or Tendergold. T Undeerstanding genetics g is th he key to growing seedless watermel ons. Seedlesss watermeloons are sterille hybrids that pproduce no fully f develop ped seeds in n the fruit. So ome immatuure edible whhite seeds may form. Prooduction of seedds to grow seeedless waterrmelons is ex xtremely lab bor-intensivee so one onlyy finds seedlless plants inn nurseries. Norm mal seeded melons m are "diploid" meaaning they have h two setss of chromossomes, one sset from eachh parent. To obtaiin a seedlesss melon seed d, a seeded parent p is treatted with colcchicine (deriived from auutumn crocuus and used to treeat gout) cau using four seets of chromo osomes to bee developedd. The resultiing "tetraploid" plant is ccrossed with h a reggular "diploid" plant to create c a "triploid" plant containing c thhree sets of cchromosomees. "Tripploid" plantss produce seedless waterrmelons. Beccause of the odd numberr of chromossomes, they are unable to foorm seeds in the fruit. Ho owever, thesse plants stilll produce fem male flowerss, but they cannot make viable polleen for fertilizzation needeed to grow frruit. As a ressult, a seededd watermeloon must be grrown along w with a seeddless variety to provide pollen p for ferrtilization an nd fruit formaation. Keep that in mindd if you wantt to grow seeddless watermelons in you ur home gard den. You mu ust grow at leeast one seedded watermeelon plant inn order to grow w any seedless watermelo ons. quire full sun n, plenty of nutrients, n waater, and rooom to vine duuring the groowing season. Wateermelons req Trannsplant seedllings well aft fter the frost date when th he soil has w warmed to 600+ degrees. Wateermelons can n result only y from succeessful pollinaation. Male fflowers appeear first on thhe main vinee runners whille female flowers appearr later on lateeral shoots. A female floower will havve a tiny maarble-sized w watermelon below w the flowerr. Once main n vines reach h about 10 feeet, if no fem male flowerss have appeaared, nippingg the main vine ends can force side shoo ot formation n leading to female f floweer production. Female fllowers also ccan be hand polliinated by dab bbing the fem male flower with a malee flower or uusing a paintbbrush. Floweers open earrly in the mornning and lastt usually onlly one day. o pick a ripe watermelon is not a sim mple task. I ussually end uup sacrificingg one or twoo until I get itt Judgging when to rightt – crisp ripee flesh witho out being graainy or mush hy. The first ttipoff to ripeeness occurss when the teendril attacching the waatermelon to the stem staarts to dry an nd turns brow wn, and the ssecond is whhen the grounnd spot, University of Marylaand Extension programs are open to all citizens without w regard to race, color, c gender, disability, religion, age, sexual oriientation, marital or pareental status, or national oorigin. where the melon rests upon the ground, begins turning from a pale green or white to a creamy yellow color. To insure the accuracy of this indicator, do not rotate your watermelons while still on the vine. Thumping is less successful for me. Supposedly a ripe melon has a muffled, dull tone while a less ripe one has a clear ringing tone. Growing your own watermelons is a lot of fun. Give it a try. You will enjoy the fruits of your labor. For more information about the Frederick County Master Gardener/Horticulture Program, visit www.frederick.umd.edu/mg or call Susan Trice at the University of Maryland Extension Frederick County office, 301-600-1596. Find us on Facebook at http://www.facebook.com/mastergardenersfrederickcountymaryland University of Maryland Extension programs are open to all citizens without regard to race, color, gender, disability, religion, age, sexual orientation, marital or parental status, or national origin.