It usually takes at-least a month or two if you are eating right and having high intake of protein. Also, it depends on how many hours are you working out in a week. Make a workout plan for ever muscle for the week and a diet plan which must include protein, iron, fiber and calcium. 

Focus on Calisthenics and Cardio to get your strength results asap

This depends upon 3 main factors: 

• How many days are you working out / week  
• If you're following a good diet plan  
• The overall intensity of your workout 

Its recommended that you visit the gym 5 days/week. I understand that it's difficult when you first start, but once you get into a routine (and maybe see some results), you'll get used to it. 

The second factor on this list (which is also the most important part) is to follow a proper diet plan. Unless you're intaking the right amount of protein, carbs, fats, etc, you won't see any significant difference in your body. They say that bodybuilding is 80% diet and 20% exercise. You won't get anywhere without the required energy. 

Lastly, the intensity of the workout also plays a very important role in strength building. That being said, it's important to start slow. Just keep following the first 2 points that you will easily be able to advance to heavier weights.    

In terms of time, you'll see a noticeable difference within 3-4 weeks (assuming you're regularly hitting the gym and following a proper diet-plan).

Hope that answers your question

Weightlifting is one of the best ways to build muscles and gain strength. But it is a very long and slow process which usually makes a person discouraged. The beginners will notice they are getting stronger relatively quickly in the first 6 months. Then from 6 months to 1 year, they will most likely gain strength about every 3 weeks. However, the muscle size can take 6 weeks to grow. It depends on your weightlifting history and your fitness goals. If you are a beginner, your workout time should be short and your body has the ability to put on a lot of muscle mass really fast, whereas if you are an intermediate or an advanced lifter, you need to spend more time in the gym and your muscle mass process will slow down. A certified sports trainer Alex Shaw says "Because the human body adapts quickly to something new, the minimum amount of time you need to actively strength train for your workout to be effective very much depends on your experience level.