Make the soil in the box or pot firm and allow plenty of space for a good watering. It is also a good idea to leave a clear half inch between the surface of the soil and the top of your container.
If you have fruit trees on you plot/garden that are any way old the it is always a good practice to remove moss/lichens or ivy. The moss/lichens can be removed by spraying with a product called Vitax 500ml Moss and Algae Concentrate. I have always found that Jayes fluid very effective but I thing that it is a banned product in some parts of the world. You could use ‘salt’ mixed with water and just poured it on to the trunk of the tree. Using this method you will more then likely have to do it two or three times. If you have a power washer it is an ideal way to get rid of the growth.
It might be good to mention that in the main; the growths do not harm the tree; it is just that some people might find it unsightly. In the case of ivy; that will harm your tree. To get rid of this ; take a saw and cut through the ivy as low down as you can. The just leave it to die. When it is brown remove the ivy from the tree.
The first sowing of celery may be made now in a heated frame or greenhouse. Sow the seeds in a shallow box filled with sifted sand, leafy soil and take care to distribute the seeds thinly. After germination, place the box on a shelf close to the rood glass to ensure sturdy growth from your seedling.
Now is a good time to sow half-hardy annual flowers that may be sown at the moment there are the charming verbenas and petunias. A shallow box is the best thing to use for this job. Fill it with finely sifted soil. Sow thinly and cover the seed very lightly with fine compost. Heat is essential to germination so if your glasshouse or polly tunnel is not heated;wait a while.
Buy your celery seeds from amazon.
Verbenas seeds from Amazon.