DELPHINIUM CULTURAL DESCRIPTION
Index:
 | Growing |
|
| Planting |
|
| Harvest |
|
| Pest control |
A temperate climate with cool nights (10 to 15 degrees C) is preferred for growing Delphinium. Daytime temperatures should not average above 25° C. Productions have a positive response to high light intensities.
During periods of low light intensity, the use of H.I.D. lights will improve flower quality and growth rate. Flower setting of Delphinium is not day length sensitive. Production is found to have improved with day lengths of 16 to 18 hours.
In the beginning of the growing period overhead watering should not cause any problems. If the spike allows it, keep watering overhead. Otherwise it is advisable to change to drip irrigation, or other methods of underneath irrigation. Delphinium needs much water. Water the plants early in the morning or late in the evening. Watering during the hottest period of the day will increase humidity and the risk of losses due to e.g. Rhizoctonia root rot. Get the crop dry as quick as possible, to keep humidity down.
The nitrogen content of the soil should not be more than twice the potassium content, considering the risk of excessive length growth.
Most preferred is 1 ˝ nitrogen : 1 potassium. When the crop starts to bloom appliance of extra potassium may be needed.
Following figures can be used as target values for the ideal fertility level of the soil.
| ELEMENT |
mmol/ltr |
mgr/ltr |
Formula |
| NH4+ |
0,10 |
1,80 |
(mmol x 18) |
| K+ |
1,30 |
50,80 |
(mmol x 39) |
| Na+ |
< 1,0 |
23,00 |
(mmol x 23) |
| Ca2+ |
1,80 |
72,10 |
(mmol x 40) |
| Mg2+ |
1,00 |
24,50 |
(mmol x 24,5) |
| NO3- |
3,00 |
186,00 |
(mmol x 62) |
| SO42- |
1,50 |
144,10 |
(mmol x 96) |
| H2PO4- |
0,25 |
14,50 |
(mmol x 97) |
| C1- |
<1,0 |
<35,5 |
(mmol x 35,5) |
| pH |
6,50 |
||
| EC |
0,90 |
Young tissue culture plants and rooted cuttings are available.
It is possible to send ex agar unrooted t.c. plants to some countries.
Put the crop support netting on the ground before planting, to make planting easier. Make small holes in the ground in which the plugs fit nicely, to get an optimal contact between plug and soil. Plant as deep as the plugs are tall. Do not damage the root system by pushing the plugs in the soil. Plant 6 ˝ plants per gross m2 for a one year culture. The plants should not be pinched.
The central branch can be harvested 3 to 4 months after planting, depending on the climate. Delphinium Elatum hybrids should be harvested when 25-33% of the flowers are open, and Delphinium Janny hybrids when 75-90% of the flowers are open.
It is important to leave about 5 to 10 cm stem on the plant for a good recovery, and to prevent entrance of rot diseases into the crown.
Delphinium Elatum will give 5 to 7 stems per year for a period of 3 years, in a good greenhouse environment. Production levels of 10 to 15 stems per plant per year are to be expected for belladonna types.
Delphinium is very sensitive to ethylene. Ethylene may cause damage like dropping of flowers, incomplete flower setting and a short post-harvest life. Ethylene damage can simply be prevented by post harvest treatment with the agent Florissant 100, which contains active ingredient silverthiosulphate. Bacteria may be troublesome also. Their influence on post harvest quality is twofold. First: the water uptake will be obstructed, which causes hanging flowers and leaves. Secondly, stems get slimy and therefore less attractive to buyers. The use of Florissant 500 can solve this problem (1 tablet per 3 liters of water).
We highly recommend post harvest treatment with Florissant 100 and 500.
Treatment: Place the flowers immediately after cutting in a bucket with a solution of 2 ml Florissant 100 per 1 liter of water, for at least 5 hours. Then put the flowers in a bucket with 1 tablet of Florissant 500 per 3 liters of water, until shipment.
Following a summary of pest control in Delphinium growing. Always test the effect of a chemical before applying it on large scale. Read the labels carefully. Do not spray any chemical on flowers. All given concentrations are to be used as an indication only and are based on 100 liters of water (grains based on 100 m2). The letter in brackets) is referring to the chemical group, for immunity reasons.
Plants are made virus free through tissue culture, but virus infection can appear. The shoots are misshapen and the growth is retrained. Yellow spots appear on the leaves, which become necrotic after some time.
Preventing/curing: virus diseased plants have to be destroyed.
A white molt appears on the leaves. On this molt a white mass of spores grow.
Preventing/curing: use 3 to 4 hours a sulfur evaporator during the night
(e) 40 ml fenarimol (Rubigan)
(f) 40 ml pyrazofos (Curamil)
100 grams of spray sulphur
Preventing/curing: keep humidity low
(a) 300 gr zineb
(b) 200 gr Eupareen
( l) 200 gr or 300 ml Daconil 2728
Preventing/curing: keep humidity low
(a) 300 gr or 550 ml mancozeb
(a) 200 gr zineb
(e) 150 ml triforine (Funginex)
(e) 90 ml Baycor flow (use Agral)
(l) 200 gram or 300 ml Daconil 2728
The leaves wilt and the plant tips over. The foot of the stem is rotten, yellow brown sclerotia are visible between the roots.
Preventing: steam soil
(b) 200 gram captan
(c) 100 gram or ml iprodion (Rovral)
Black spots appear on the leaves of Delphinium Elatum , mostly bounded by the veins.
Preventing/curing: take care of sufficient root pressure during the night to
l. Spider fly
Preventing/curing: (b) 50 gram Torque plus interval 7-10 days
(e) 100 gr. or ml Pentad interval 7-10 days
(g) 25 ml Abamectine interval 7-10 days
(r) 70 ml Aseptacarex interval 14 days
Causing leave and bud damage
Preventing/curing: (k) 50-100 gram Bacillus thuringiensis
(o) 50 gr or 25 ml Dimilin (a) 100 gr or ml Parathion
(a) 75 ml Mevinfos (a) 50 gr Orthene
(a) 100-150 gr Dipterex (p) 100 ml Nomolt
(d) 100 gr or 125 ml Methomyl (f) synthetic pyrethroid
Can cause enormous damages in Delphinium, by eating the young shoots.
Preventing/curing: (c) 50 gram methiocarb grains
(s) 70 gram metaldehyde grains