From Dirt to Water: Cloning a Tomato Plant

Next after basil and watercress, the plants I most enjoy growing in water are tomatoes.  They are easy to start from seed, but sometimes it is faster, and just as economical, to clone them from cuttings.   In another article, I described making hydroponic planters out of one-quart plastic milk bottles.   Pictured here is one of them, housing a newly rooted tomato plant.

The milk bottle makes a good plant container because the inverted top fits snugly into the base.  That reduces the amount of evaporation so that it doesn’t have to be topped off with water too often and the cost of the liquid nutrients doesn’t evaporate into thin air.  Any soluble fertilizer will do, but I prefer to use General Hydroponics Flora series for my clones, starting out with a weaker solution and then as the plant strengthens and shows rapid growth going to about 2 ml each of the Gro, Micro, and Bloom until flowers appear.  I store small amounts of the GH in small capped syringe of the sort that are used for medicating infants.  These hold 10 ml each and I keep them in a hinged recipe box for neat storage.  When buds begin to show, then I start using Green Light tomato bloom spray about once a week, while reducing the Gro by half and doubling the Bloom. 

The plant pictured is a determinate (bush) tomato, but indeterminate (vining) varieties can be cloned to grow in small indoors planters, too.  For those, it is advisable to put a stake in the container at the time of planting in order to avoid disturbing the roots later on.  Last season, by wrapping it around and around the same support. I cloned a currant tomato vine that grew 25 feet long before the tiny but sweet and delicious fruit petered out.    I had vigorously pruned back the suckers while shaping the plant, but instead of throwing them away, rooted them in water to make more plants, so the harvests continued.  

Tomato cuttings take about 4 days to root and do not require a hormone.  Unlike some plants, which must be carefully pruned, roots will form anywhere on the stem.   For all my plants  I use filtered water, as plants do not like the chlorine in tap water, but in a pinch it is sometimes possible to just set ordinary tap water aside for a day or two before using it on the plants.  This depends on your water supply and what kind of chemicals have been added to it.  Some evaporate out better than others.   Since we have a Doulton gravity filter on hand for emergency use, that is where I get my plant water.  The ceramic filter lasts for years and only needs to be scrubbed with fresh water and a brush once in a while as maintenance. 

The hydroton rocks/clay pellets not only hold up the stem and keep the plant erect, but they also help aerate the water.  Some water gardeners boil them between uses, but I just rinse them off and then set them out and let the desert sun disinfect them.   When I arrange a newly rooted clone for the first time, I put a few less expensive stones and then the larger clay pellets in the bottom and then sprinkle smaller diameter pellets in last.  Putting the small stones in on top anchors the tender young stems better, and also helps reduce evaporation and algae growth by blocking light.  In high light areas it is also a good idea to put some sort of cover over the top of the rocks.  I usually just make cut-outs from plastic lids such as are packaged with  inexpensive storage containers sold in dollar stores.   Readers of my gardening blog call them “Ann’s Blue Mulch.”

The idea is the same. 

This sort of container can be used to grow outdoor plants, too, but one thing to keep in mind if your plants are housebound, is that in order to bear fruit, flowers need pollination.  For tomatoes that is an easy thing, since these plants are wind-pollinated and do not require bees.  All one has to do is shake the stems every day or two and the pollen will distribute itself according to nature’s plan and before long incredibly tiny round green balls will start cropping up here and there.

The plant pictured above promises to grow quite large, so at some point I will be lifting the insert together with the grow rocks and tomato plant intact out of its base and nestling the whole thing inside a well-washed spigoted laundry soap container with the neck cut open and filled with larger hydroton rocks.  Since the roots will not be disturbed, transferring to a larger container will not interrupt the growth.  As with the vining tomatoes, however, it is a good idea to put a stake in the new container now instead of trying to do it later. 

When the plant has been transferred to the larger container,  instead of lifting the insert out twice daily to aerate the roots, I will just open the spigot and let the nutrient solution drain into a bucket, then pour it back over the top.   People who don’t want to be bothered with doing that can, of course, set up an external fish tank pump next to the planter and drop an air stone into the water to get the same effect without having to buy expensive hydroponic equipment.   But that requires a power source.  I like to keep it simple.  After all, my purpose in having plants, in addition to eating their fruit, is to bond with them.