Lemon seedling repot/fertilizer question

[LemonBonsai]

So I repotted this lemon of mine maybe 2 weeks ago? Not to sure but it was something like that. All im wondering is when can I give it some fertilizer? I did do some light pruning to the roots but not to much. My idea is to wait until it starts pushing new growth, is this the right thought? Or should I be giving it a little bit to give it more resources to start pushing new growth?



Ps. i know I should put it in a bigger pot to get the trunk to thicken up more, im just at test stages right now in my bonsai journey, I have another in a bigger pot and want to see the different for the summer

And I also know I repotted a bit early

 

[Shibui]

Citrus typically don't start to grow much until late in spring and summer. Growth is determined by temperature and day length, not by fertilizer so I don't think adding fert will kick start growth if conditions are not yet right.
It will definitely be safe to add fert now but whether it will be effective at this stage may be debatable.
I would probably opt for a light dose now, building up as you see new shoots later in spring.
When to fertilize depends somewhat on what sort of fert you use. Liquids are generally instantly available to the roots so add when actually needed. Organic fert needs to break down a bit to release nutrients that plants can absorb so organic fert should be added a few weeks before the plant will need it.