Lars Lund

16 Feb 2023 09:06

Status in the greenhouse in February

We are heading in the right direction and the first spring flowers are upon us. Let’s get started.  

Even though February is one of the coldest months, the sun is higher in the sky and that means the greenhouse soil gets some extra heat. But there is another side effect of the sun shining – it becomes obvious that the glass of my greenhouse needs a serious clean. I must get right on it. It is best to clean the glass on a cloudy day without any frost, to avoid any stripes. At the same time, I can wash away any fungi and overwintering pests or their offspring.


How to clean your greenhouse

Empty the greenhouse

February is a good month to wash and clean your greenhouse. I begin by emptying the greenhouse and cleaning all loose items and furniture. Afterwards, I continue inside the greenhouse by cleaning the glass. I either use a garden hose or a spray bottle, that I fill up with “Bio-clean” from Juliana. Bio-clean is a biodegradable cleaning solution, with the right pH-value to break down fungi. I spray it into every nook and cranny and let it set for about a half an hour - just enough time for a cup of coffee. Then I grab a brush and scrub all the dirt away. Lastly, I wash away all the dirt and leftover cleaning solution with a garden hose, both from the inside and outside of the greenhouse. Alternatively, it is possible to use a use a high-pressure cleaner.


The floor

In the majority of my greenhouse, I have a brick floor. Bricks can absorb moisture, especially if they are not hard-burnt, and therefore there are algae in some places. I have a special brush for the high-pressure cleaner to clean the brick floor. However, if you don’t have that, just use a floor mop and some chlorin or Bio-clean – that also removes the algae. If I’m in a beachy mood, I put beach sand on the floor. I can always sweep it away when it’s not pretty anymore.

Don’t forget the gutter

Even though the gutter of my Oasis has a lid, there are always some leaves that find their way in and especially moss tends to stick. When the gutter is clogged this way, water gets in the greenhouse easily. So, take off the lid and clean out the gutter.


Fresh soil is like a fresh set of sheets

The soil in the greenhouse needs a check as well. I grow in both grow bags and beds. The soil from the grow bags, I have already spread in the kitchen garden and beds in November. I will also change some of the soil in my greenhouse beds. Once we used to change the soil in the beds up to a spade deep, but that is not necessary. It is enough to just change the first 4 inches. For that I use compost and I find that it makes most sense to use soil I make myself. Even though I only change the soil down to about 4 inches, I try to use crop rotation in my beds. Every 5 years, however, I do exchange the soil a spade deep and basically swop around the soil from the kitchen garden and the soil from the beds in my greenhouse. This process works really well in my garden.

The first seeding

Last fall, I placed some flower bulbs in pots, and the first snowdrops and flower bulbs are already in full bloom. Soon the daffodils and tulips will follow. Otherwise, it is now that I sow broad beans, kale, corn salad and a little spinach too. Spinach grows quite slowly, but spinach sprouts taste quite delicious too, if you can’t wait.  I also have planted a rhubarb pant from my garden in a pot to be placed inside the greenhouse.


Time for potatoes

On my windowsill, the germination of potatoes, and chillies, that need an early start, are in full swing. In late February, the sprouting potatoes are put in buckets and placed in the greenhouse. If there is frost, I cover them or place them inside again, if the weather forecast predicts harsher weather or long-term frost.

Out in the open, up against a south facing wall, I have figs. In milder weather periods, apricots, nectarines, and peaches can bloom in the greenhouse already now. If there are no bees, you need to play a bee yourself. Grab a small brush and turn it around in the blooming flower, so that the pollen will transfer from the stem to the stigma. 


A heating bed

Right outside the greenhouse, I am making a heating bed. The heating bed is built from horse manure and soil and creates amazing heat from the bottom. This provides the vegetables with a great start and makes it possible to cultivate potatoes early. Remove about half a meter of soil. Fill in 10 inches of horse manure, 2 inches of soil, 4 inches of manure and lastly 4 inches of soil. The horse manure provides heat and later also nutrients for the plants.

Cleaning the pots

I have a lot of pots that have been used during the season. I never have the time to clean them after they have been emptied, but now they need a good scrub. The pots have some green patina on the outside, that I won’t clean, but the inside of the pots get a good scrub. I have a workstation outside the greenhouse with a sink, but I haven’t turned the water back on after the winter. Therefore, I take a bucket with lukewarm water to clean all my pots.



Now, all that is left, is for me to sit down and enjoy a nice cup of hot tea in front of my small wood-burning stove. It is quite lovely to smell the fresh soil, enjoy a freshly washed greenhouse and be able to see the garden through my clear windows and think to myself; it is not long now until the world outside becomes greener.

Om Lars Lund

Lars Lund
Danish horticulturist and journalist
Lars Lund has for many years engaged in the garden and greenhouse. Lars has published many books about greenhouses, and he has participated in many Danish horticultural TV shows. He is a walking garden encyclopaedia, and he has answers for most basic cultivation questions – also the more ambitious ones.  

Get to know Lars Lund