Southeastern U.S. Vegetable Crop Handbook - 2023 - 17

rascus vine decline, Phytophthora blight, root-knot nematode,
and other soilborne diseases.
Additionally, grafting can enhance tolerance to abiotic
stress; increase water and nutrient use efficiency; extend harvest
periods; and improve fruit yield and quality in certain cucurbits.
There is a wide array of potential rootstocks: Lagenaria spp.
(bottled gourd), interspecific squash hybrids, wild watermelon,
or melon. These rootstocks can produce vigorous plants with
resistance to many soilborne diseases. However, each rootstock
type provides advantages or disadvantages under certain environmental
conditions. Check with the transplant grower to see
which rootstock they would recommend for your area.
Grafting Methods for Cucurbits. Grafting in cucurbits is the most
difficult to do and continuous practice is needed to be successful.
There are four commonly used methods to date: tongue approach
graft, hole insertion graft, one cotyledon graft, and side graft.
Only one of these methods is currently automated (one cotyledon
graft method). The other three methods are labor intensive.
Remember that grafting is an art that requires attention to detail.
The major concern with cucurbit grafting is the constant threat of
regrowth of the rootstock, which needs to be removed by hand.
Additional information can be found at
http://www.graftingvegetables.org.
Grafting Methods for Tomatoes. There are three primary techniques
used for grafting tomatoes: tongue approach grafting,
cleft grafting, and tube (or clip) grafting. Cleft grafting and tube
grafting are similar in that the shoot of the fruit-producing scion
is completely cut off from its own roots and attached to the
severed stem of the rootstock. The name 'tube grafting' originated
because when the technique was first developed; a tube
was used to hold the shoot and the rootstock together. Clips are
now used to make this graft. Tube grafting is quicker and less
TABLE 7. POPULATION OF PLANTS PER ACRE AT SEVERAL BETWEEN-ROW AND IN-ROW SPACINGS
In-row spacing (in.)
2
4
36 (3 ft)
42 (3.5 ft)
48 (4 ft)
60 (5 ft)
72 (6 ft)
84 (7 ft)
96 (8 ft)
87,120
74,674
65,340
52,272
43,560
37,337
32,670
6
87,120
58,080
49,783
43,560
34,848
29,040
24,891
21,780
17,424
14,520
12,446
10,890
8
65,340
43,560
37,337
32,670
26,136
21,780
18,669
16,335
13,068
10,890
9,334
8,167
10
12
18
21
24
30
448,046 224,023 149,349 112,011 89,609
261,360 130,680
174,240
149,349
130,680
104,544
87,120
74,674
65,340
52,272
34,848
29,870
26,136
20,909
17,424
14,934
13,068
10,454
8,712
7,467
6,534
TABLE 8. CRITICAL PERIODS OF WATER NEED FOR
VEGETABLE CROP
Crop
Asparagus
Beans, Lima
Beans, Snap
Broccoli
Cabbage
Carrots
Cauliflower
Corn
Cucumbers
Eggplants
Lettuce
Melons
Onions, Dry
Peppers
Potatoes (Irish)
Radishes
Southernpeas
Squash, Summer
Sweetpotato
Tomatoes
Turnips
Critical Period
Brush
Pollination and pod development
Pod enlargement
Head development
Head development
Root enlargement
Head development
Silking and tasseling, ear development
Flowering and fruit development
Flowering and fruit development
Head development
Flowering and fruit development
Bulb enlargement
Flowering and fruit development
Tuber set and tuber enlargement
Root enlargement
Seed enlargement and flowering and English
Bud development and flowering
Root enlargement
Early flowering, fruit set, and enlargement
Root enlargement
2023 Vegetable Crop Handbook for Southeastern United States
12
74,674
43,560
29,040
24,891
21,780
17,424
14,520
12,446
10,890
8,712
7,260
6,223
5,445
14
64,006
37,337
24,891
21,336
18,669
14,935
12,446
10,668
9,334
7,467
6,223
5,334
4,667
16
32,670
21,780
18,669
16,335
13,068
10,890
9,334
8,167
6,534
5,445
4,667
4,084
18
29,040
19,360
16,594
14,520
11,616
9,680
8,297
7,260
5,808
4,840
4,149
3,630
24
21,780
14,520
12,446
10,890
8,712
7,260
6,223
5,445
4,356
3,630
3,111
2,722
30
17,424
11,616
9,957
8,712
6,970
5,808
4,978
4,356
3,485
2,904
2,489
2,178
36
14,520
9,680
8,297
7,260
5,808
4,840
4,149
3,630
2,904
2,420
2,074
1,815
48
10,890
7,260
6,223
5,445
4,356
3,630
3,111
2,722
2,178
1,815
1,556
1,361
TABLE 9. AVAILABLE WATER-HOLDING CAPACITY
BASED ON SOIL TEXTURE
Soil Texture
Coarse sand
Fine sand
Loamy sand
Sandy loam
Fine sandy loam
Loam and silt loam
Clay loam and silty clay loam
Silty clay and clay
Available Water Holding Capacity
(water/inches of soil)
0.02-0.06
0.04-0.09
0.06-0.12
0.11-0.15
0.14-0.18
0.17-0.23
0.14-0.21
0.13-0.18
Between-row
spacing (in.)
7
TABLE 10. SOIL INFILTRATION RATES BASED ON
SOIL TEXTURE
Soil Texture
Coarse sand
Fine sand
Fine sandy loam
Silt loam
Clay loam
Soil Infiltration Rate (inch/hour)
0.75-1.00
0.50-0.75
0.35-0.50
0.25-0.40
0.10-0.30
17
http://www.graftingvegetables.org
Southeastern U.S. Vegetable Crop Handbook - 2023

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