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System Design
Plant Propagation
Water Quality
Stock Solutions
Pre-plant Routine
Post-plant routine
Quality Control
Media Sampling
Root Disease
Nutrient Levels
Nutrient Uptake
Greenhouse management Tomato crop management Management of alternative greenhouse food crops. Crop Nutrition

Procedure prior to planting

Greenhouse Clean and Trickle irrigation clean and check.

1. Spray the crop with an appropriate broad spectrum insecticide to eliminate any insect pests that may be present in the old crop. This is for your own safety, as crop removal disturbs the pests, which migrate to your other crops or to your neighbors crops.

2. Turn off irrigation system and allow the plants to dry out the root mat.

3. Remove old crop, and consign to the dump. Remove old bags there has been disease problems, excessive salt build up or if they are past their best. Most greenhouse properties are too small to allow old crop remains to be dumped on the property without risk of disease persistence in the dump and future re-infection of your own or neighbours crops. If the old plants do have to be dumped on your own property then they should be either burnt, or buried with soil or at least covered over with polythene.

4. Sweep up and remove all loose and plant debris and dust.

5. Wash down all interior greenhouse surfaces and floors with a high pressure water wash.

6. Fumigate or disinfect the greenhouse either by spraying formalin or thermal fogging with formalin if this is legally available for use in your location. Use formalin at 1 litre of formalin in 50 litres spray or about 1 litre formalin per 150m2 of greenhouse floor area. For thermal fogging use 400ml formalin per 100m3 greenhouse space. Do not use stale formalin, it polymerizes on keeping and is not effective. Good protective clothing is required and a respirator cannister rated for use with formalin. It is best to do this during the afternoon while it is still warm and to shut the greenhouse tight overnight. Ventilate the following morning and do not work in the greenhouse until the smell of the formalin has dissipated. It is also possible to use a strong chlorine solution of 100ppm or a commercial solution that contains the active ingredient of Alkyl-dimethyl-benzyl-ammonium chloride. Rinse well afterwards twice or three times. Protective clothing is also required with both of these materials.

7. Wash overhead crop wires and any cradle wires using a disinfectant. A squeegee mop on a long handle is most effective for this, as the sponge can be clamped around the wire while pushed down the length of the wire. Wash and wipe any surfaces likely to be regularly handled by dirty hands, e.g. door handles, ventilator winders etc.

8. Wire string hooks, cradle wires or any other plant support parts which are to be re-used should be soaked in disinfectant before being brought back into the house.

9. Thoroughly clean and check the trickle irrigation system which helps to avoid many problems during the growing season. The following notes assume that the outside of the trickle system pipes has been cleaned during the end of crop clean up. If not the pipes should be water blasted or washed clean of any dirt or algae before proceeding with the following steps.

10. Open the ends of the flow headers and flush out the header pipes with clean water.

11. Disconnect the lateral pipes from the headers.

12. Open the far ends of the lateral pipes and connect the header end to a hose pipe and flush out the lateral with clean water.

13. Close the far ends of the lateral pipes and flush clean water through the microtubes or drippers using as much pressure from the hose pipe as possible. The microtubes should all be squirting water very strongly. Check for any missing microtubes. Check that each microtube is flowing strongly and unblock or replace any microtubes not delivering the full flow. Make sure that any replacement microtubes are the correct length and bore.

14. Re-connect lateral pipes to headers.

17. Each station of the irrigation system should have a clear plastic sight tube to indicate the normal operating head. Clean these clear plastic tubes by pulling through a piece of rag on a wire or replace if the plastic is discoloured and cannot be cleaned.

18. The water and feed supply to microtube trickle systems should pass through a filter (preferable 200 mesh or equivalent). Check and clean the filter.

Preparation for planting.

1. Preplant wetting
Wetting before planting is necessary to ensure that all the bags have the same moisture content and that all the media within the bags is uniformly wetted. Failure to properly prewet bags may result in uneven plant establishment and of funnelling of water straight through the centre of the bags and out the bottom without any lateral wetting of the media. Stand out planter bags in final position and install microtubes or drippers. Hose water bags with plain water until water runs out the bottom of the bags. If modules are to be used place modules in position but upside down (i.e. any prepunched drainage holes on top). Insert microtubes into the bags and apply water until bags are full of water. Then turn bags the right way up, cut drainage slots if bags are not prepunched, and allow to drain overnight.

2. Preplant feed
Apply about 1 litre of feed per bag (assuming bag of about 8 - 10 litres is used) through the trickle irrigation, using feed at CF 20-25.

3. Planting
Not all plants will be top quality so select good healthy plants of uniform size for planting keeping plant size uniform within rows.
Ex plastic pots : knock out plant carefully, so as not to disturb roots, and plant with cotyledons (seed leaves) just above the surface of the sawdust or pumice.
Peat pots: plant with the rim of the peat pot just buried in the sawdust or pumice but the cotyledons must not be buried. Bottomless plastic pots : stand pot with plant on the surface of the sawdust or pumice or bury to a depth of 20-25 mm for better anchorage.

4. Spare plants
It is worth setting up an extra half row with a trickle line in a path for spare plants, planted into planter bags as usual. These spare plants can then be used to replace any plants that are not upto standard, or become damaged or diseased prior to setting the fourth truss. At that stage any unused spares need to be discarded.

5. Microtubes or drippers
Make sure that the microtubes or drippers are discharging onto the root balls of the plants.

5. Post-plant Feed
Apply 150-200 ml of feed per plant immediately planting is finished.

6. Apply sand to sawdust
Much better water spread is obtained in sawdust bags is the bag is topped with a 10-15 mm layer of fine sand. It is easiest to apply the sand after planting and before stringing.