Things to do in January
Fuchsias in January;
In the heated greenhouse, you should still be checking your plants on a regular basis. The greenhouse needs to be ventilated on all but the coldest days to minimise botrytis problems.
Plants in green leaf need to be regularly checked for insects and disease and turned through a quarter turn to prevent growth towards the light. Sparse watering when needed and a spray with water containing low strength high nitrogen fertiliser such as Chempak No 2 and Maxicrop will be beneficial on sunny days. Plants that are dormant need to be sprayed with warm water on sunny days to soften the wood and encourage the buds to break.
Any plants not re-potted in the autumn should be re-potted in the next two months. As a guide you will normally be able to pot back by 25% i.e from a 15cm pot back to an 11 or 12cm pot. Cuttings can be taken from suitable growth in a heated propagator or a hot bench or rooter inside the house in a windowsill propagator. If you have a gas heater run on propane from bottles, make sure you have a spare full bottle available. The best is to have an auto-changeover valve installed which ensures against the bottle running out on the coldest night of the year (as it invariably does!)
Please note your greenhouse should only be half full at this time of year unless you have additional greenhouses you can expand into during the spring before plants can be permanently moved outside.
If you are overwintering in a cold greenhouse by covering plants with fleece, then remove the fleece from time to time to check the plants have not dried out. Many exhibitors who grow in the Midlands and northwards grow through the winter on heated benches which minimises the need for space heating and gives more rapid growth in December through to February.
Pelargoniums in January;
Things to do in February
Fuchsias in February;
In the heated greenhouse, plants will be beginning to move as the temperature starts to rise on sunny days. Continue to turn all plants through a quarter turn every 2-3 days and water when necessary.
Watering from the bottom of the pots by standing in saucers or similar at this time of year can help to minimise botrytis by keeping the compost at the top dry. Every time you pick up the pots check for any signs of disease or pests especially by looking under the leaves.
Remove any dead or yellowing leaves. If necessary start to pinch out the growths on show plants, if possible all at the same time. If there are any very strong growths, especially coming from the bottom of the plant, cut these back a bit harder to prevent the plant becoming misshapen.
Complete any re-potting of plants during this month. Also during this month, the growths are long enough to start taking tip cuttings. The best of these consist of one set of leaves and a growing tip. The stem below the bottom set of leaves can be cut either between nodes or just below the next available node. These should be set into a mixture of sifted Irish moss peat or seed compost with equal amounts or Vermiculite, Perlite or a mixture of either of these with grit or washed sharp sand. Set these in a propagator either with a bottom heat of 15°C or an unheated propagator in a heated greenhouse. Cuttings in the former will root in 2-3 weeks, in the latter in 4-5 weeks.
Remember to ventilate the greenhouse at every suitable opportunity.
Pelargoniums in February;
Things to do in March
Fuchsias in March;
On sunny days the greenhouse will reach temperatures in the mid twenties, (°C) so maximum suitable ventilation is very important. Conversely, temperatures may still drop to below freezing at night, so heating will still be necessary overnight. Lush new growth can easily succumb to botrytis so carry on the regime of removing any yellowing or dead leaves, but also remove or cut in half any large leaves which are touching each other or blocking light from shoots growing underneath.
Plants can be potted on when necessary. I prefer to pot on through several gradually increasing pot sizes to maximise the roots use of the compost. Normal plants can be potted on when the roots have curled around the bottom of the pot. The exception to this is growing a standard whip or stem, where it is very important that the plant does not become at all pot bound while the stem is growing. Pot on as soon as the roots reach the bottom of the pot and feed only with quarter strength high nitrogen feeds such as Chempak No 2.
On suitable days in late March it may be possible to stand some of your plants outside in the day to help to firm up the new growth. Take care not to do this with any cultivars whose leaves mark when exposed to sudden temperature changes. Examples of these are Marinka, Border Raider and Nellie Nuttall.
It is still very important to keep regularly turning your plants, but also stopping them to shape them. In these early stages of growth, many shoots may just have the growing tips removed, but other stronger growing shoots may need to be cut back harder. If possible try to stop all the growing tips at the same time.