Connie H One of the joys o

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Frederick, Maryyland 21702
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Growing Waterm
Connie Holland,
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
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.
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.
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.
Seedeed main season watermellons also com
me in yellow
or orrange-fleshed varieties such as Desert King or Tendergold.
Undeerstanding genetics
is th
he key to growing seedless watermel ons. Seedlesss watermeloons are sterille hybrids
that pproduce no fully
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.
mal seeded melons
are "diploid" meaaning they have
two setss of chromossomes, one sset from eachh parent. To
obtaiin a seedlesss melon seed
d, a seeded parent
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
a reggular "diploid" plant to create
a "triploid" plant containing
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
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
w any seedless watermelo
quire full sun
n, plenty of nutrients,
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
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
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
regard to race, color,
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
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 or call Susan Trice at the University of Maryland Extension Frederick County
office, 301-600-1596. Find us on Facebook at
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.