I have wanted to grow grapes for a while, but as usual, I found it difficult work out the right place to grow them. After some thought I decided to grow them up under the cover over the back deck, that way as well as grapes we would have shade in summer and sun in winter. There are some issues to be overcome with this approach, mainly around making sure the grape gets enough water without overflow or drainage staining the timbers of the deck. So this is how I got around it.
The Pot
Our local shops have some black 30 litre pots with rope handles which seemed ideal for the purpose. The black plastic is very resistant to the sun – witness the self-watering pots which have been in the back yard for 7 or 8 years and still doing great service – so black it was (not that there were any other colours…….but you know what I mean!) Normally I would drill 12mm holes in the bottom for drainage, but as mentioned above I didn’t want it discolouring the deck timbers so I chose a the following approach.
I put in a drain about 25mm up the side of the pot by drilling a 22mm hole with a spade bit and inserting a 15mm male to female irrigation adapter and screwing onto it a 19mm barb x 15mm BSP female threaded elbow. This allows any excess water to run out of the pot to the side, without making a mess of the deck. To ensure drainage, I mounded up some pebbles on the inside of the pot, around the drainage hole so the growing medium would not block the drain hole.
Water Reservoir
To provide a water reservoir in the pot so that the grape has a plentiful and continuous water supply I made a buried capsule to go in next to the grape when I planted it into the pot. I got hold of a 20cm unglazed terracotta pot and similarly sized terracotta pot saucer with which to make the buried capsule.
To start I installed a fitting with a 19mm thread on one end and a 15mm BSP barb fitting on the other into the drain hole of the terracotta pot. (you need two per capsule). To help secure the fitting into the capsule I butchered a Garden Rain 15mm Female to Female Rural Poly Irrigation Coupling and to join the reservoir to the capsule a length of 19mm clear vinyl tubing. One fitting is screwed into the drain hole of the pot and then the vinyl tubing is used to secure the two barbed fittings end-to-end. (for more detail see here)
To complete the buried capsule I siliconed the pot saucer to the top of the pot, creating a watertight capsule which is filled with water through the open end of the fitting secured in the drainage hole. The whole assembly is then buried upside down, so that the fitting sits above the soil surface.
I then placed some potting mix into the pot, installed the buried capsule and the grape vine, and filled the pot with potting mix ensuring that the grape was buried such that the soil surface is the same in its new position as it was in the original pot.
Something to Climb On
The idea is that the grape vine will now climb up one of the deck roofing supports and then spread out under the deck roof. It does, however, need some way of climbing up the supporting timber. I cast around to find something which would do the job effectively (but hopefully cheaply) and found some lattice which was designed to be used horizontally as a fence (it was 1800mm x 300mm border fence). All I needed to do was trim off the two spikes which would be used to secure it into the ground if it was being used as a fence. I then screwed on a couple of supports and then screwed the supports onto the deck roof support, and there you have it!
It is still early days and it will be interesting to see how the grape vine develops. I am assuming it will take several years to get where I want it to go, but I have the time.
