Transplanting part 3 - 18/01/08

I plan to grow my cabbage plants this year in a hydroponic drip systems know as the 'wilma'. The plants will be grown in a mix of coco coir (80%) and perlite (20%) so I prepare enough of the growing media to fill 10 small square pots.

Once the pots are filled the seedlings are planted in and water through with a coco coir specific nutrient solution (I use vita link coir or canna coco) at an EC of 1.2. I always water until there is solution running out the bottom of the pot to ensure all the media is sufficiently damp. The perlite helps increase the air spaces in the mix stopping the coco staying too wet, creates better drainage and helps stop compaction.

Now I've got all the seedlings planted up into larger blocks or pots they are arranged on the air pruning tray and the light is lowered to get an even distribution of light to all the plants.



To keep the relative humidity between 65-75% I have a humidification system controlled by a humidistat. Before i used these devices the relative humidity would be around 30-40% plant health was quite poor. The white Humidifier in the picture is a centrifugal HR-50 and the mist coming out the black tank is produced by 2 ultrasonic 5-disk mist makers. The mist produced by both devices is cool and in summer helps to lower temperatures too.

Transplanting part 2 - 18/01/08

Now the rockwool blocks have been soaked I get the planting area prepared. When propagating my plants i keep the temperature in the growing area between 22-25c and the relative humidity between 65-75%. Young plants respond and grow very well in humid environments. I use 110w fluorescent lamp on for 18 hours a day to supplement the natural light entering the greenhouse.

After the transplant blocks have been pre-treated they need preparing for the seedlings to be planted into. Rockwool holds allot of water so after soaking excess needs to be shaken out or lightly squeezed. I Shake a few times then lightly squeeze (squeezing heavily can damage the structure of rockwool). The blocks want to be damp but not too wet. You can tell when they ready by squeezing the corners lightly, if no solution drips out your ready to plant in.

Once the blocks are all ready I insert each propagation cube into their blocks. I make sure the cubes are firmly in to avoid leaving gaps between the cube and the block.



To avoid algae growing on the surface of the rockwool blocks i cover them with squares of black and white plastic. You can cut them your self but i buy pre cut squares as they are cheap and saves loads of time. Another good thing about the white plastic squares is you can use them as labels to identify the plants too.

I always put my plants growing in transplant blocks on a raised mesh so air can move underneath them. This slight movement of air under the blocks stops roots growing out and concentrates the root growth within the block, this is know as 'air pruning'. I use to place blocks on a growing media such as perlite or vermiculite in a tray but this encouraged the roots grow straight out the block and into the media. When the plants were moved the long roots out of the block inevitably got damaged. These young damaged roots would often die back not getting the plant off to a good start so now I always use air pruning trays until the bottom of the block is covered with root tips. This always gets plants off to a explosive start with less chance of transplant shock when planted into its final hydroponic system.

Transplanting Part 1 - 17/01/08

The seedlings have been in the propagator for 2 weeks and have established well into their propagation cubes. Now they are ready for planting into larger rockwool blocks, jiffy coco coir blocks or pots.

I usually decide to transplant the seedlings when the first 'true' leaves are through (after the first 2 round dicotyledons) and/or the propagation cube has roots growing out of it. Notice how the roots growing out of this rockwool cube are very white and healthy.

The plants final hydroponic system usually determines what they are transplanted into. I mainly use 4 inch rockwool blocks which are the most flexible choice as they are suited to nearly all systems. The picture shows the transplant blocks prior to soaking.

The soaking solution is measured using digital pH and EC meters. The rockwool blocks are soaked using Vita link Plant Start and Vita Link Bio Plus, added at the recommended dose the pH

measures 5.5 and EC of 1.5.

The pH will rise to around 5.8-6 a few hours after the rockwool is added. Some growers will use a lower Nutrient strength (EC) whentransplanting seedlings but I find and EC of 1.5 stimulates good growth with no negative effects.

The Jiffy coco coir blocks allready contain nutrient so only need to be soaked in water although a root stimulator can be used. After soaking squeeze off the excess solution that the coir will hold.

Germination - 14/01/08

After 4-5 days the tomato, cucumber, cabbage and melon seeds started to pop up. After 10 days so did the chilli peppers , sweet peppers and onions. Before I used a heated propagator germination rates were allot slower with chillies and peppers taking up to 3 weeks, I'm very pleased with how quick they've all come up this year.

Now most of the seedlings have germinated i open the vents on the propagator to lower the humidity inside slowly getting them ready to be taken out into the less humid greenhouse. Once the roots are clearly showing on the propagation cubes I'll be ready to transplant them into larger blocks/pots, this usually takes another 4-5 days.

Sowing the Seeds - 09/01/08

January's the time I sow the seeds of my main crops which are tomatoes, chillies, peppers and cucumbers. For propagating my seedlings I use Grodan Rockwool cubes and 'Fleximix'.

'Fleximix' is a peat/pine bark based spongy cube bound together using a plant based polymer. It has a great air to water ratio suitable for seeds and cuttings. These cubes are taken straight out the bag, put into small trays and wet using a spray gun. They come slightly damp but often need a bit more wetting. You can squeeze off any excess water applied as they easily spring back to shape. They already contain some plant nutrients so do not apply any more at this point.














Rockwool cubes are made from heating up volcanic rock into liquid and spinning it like candy floss into blocks. These are then cut into shape. Rockwool contains no nutrients for plants so needs pre-soaking in a mild nutrient solution. I use 'Vita Link' Plant Start at the recommended dose which is high in all the nutrients young plants need. I also use a liquid formula of beneficial microbes , fungi and bacteria called 'Bio Link Plus'. This stuff smells so bad but is great at producing a great root system.

Rockwool should be soaked for at least a few hours but overnight is preferable. Rockwool is also slightly alkaline so before soaking check the soaking solution is around pH 5.5 (near the lower limit which plants can tolerate). I find after mixing the 'Plant start' and 'Bio Link Plus' the pH falls around 5.5 so no further adjusting is necessary. After a few hours the pH of the solution will raise up to between 5.8-6.0 which is considered optimal for plants grown in hydroponics. When I take the cubes out of their soak I give them a few shakes to get rid of any excess solution. Saturated rockwool can hinder germination and welcome diseases. Another way to remove the excess is to lightly squeeze the cubes but I find this can disrupt and compress the structure of rockwool so prefer to shake them.














After the propagation cubes are prepared I write all my labels and make small holes 1 or 2 cm deep for planting the seeds into. Once the seeds are planted into the holes I lightly close them back up to keep the seeds dark. When using fleximix I fill the pre made holes using some fine compost, coco coir or loose bits of fleximix.














Once all the seeds are sown and the trays are labelled I place them in a large propagator heated using a Thermostatically controlled heating mat. On the base of the tray I use dampened Vermiculite or Perlite which spreads the heat evenly in tray and holds water to keep the propagator humid. Seeds germinate quickly in a heated propagator which is essential if your growing area is a bit cold. I try to manitain the propagator around 24c and above 85% Relative Humidity. I find this gives me good results especially for chillies and peppers. Hanging above the propagator is a 110w fluorescent twin lamp (2 x 55w bulbs) which doesn't use loads of electricity and brings on the seedlings extremely well once they pop up.















Once the lid is closed the humidity soon builds up inside. Now all I can do is wait and see. Hopefully in 1-2 weeks I'll be ready to transplant them!

Starting from Scratch

This year I decided to give the greenhouse a thorough clean down. The polycarbonate panes were cleaned inside and out to improve light transmission and the floor was given a new lick of paint. This had not been done for a few years and looks allot better, it will also kill off any plant pests that may have be lingering or hiding from last years crops.

The Greenhouse

The greenhouse we have at Aquaculture is a 'Venlo' design by Cambridge Greenhouses. It is fully heated via hot water pipes and is ventilated through vents on the roof. The computer system installed controls the roof vents and the heating pipes. It's Size it is approximately 5m x 15m which is big enough to display all the products we sell as well producing an abundance of fruits and vegetables. All the growing systems I use in the greenhouse are considered hydroponic which means the plants are not grown in soil.